Search

BRAF p.V600E exon 15 hotspot mutation can identify a molecular subgroup of metastatic colorectal cancer (mCRC) patients exhibiting poor prognosis under the conventional chemotherapy regimen. Recently, the chemotherapy-free combination of encorafenib and cetuximab has been approved as the standard of care for previously treated BRAF p.V600E mCRC patients, and genomic testing for BRAF mutations at the time of mCRC diagnosis is currently recommended. In clinical practice, BRAF mutation testing strategies are dramatically impacted by a lack of harmonization and standardization, both in the pre-analytical and analytical phases, which can result in BRAF-mutated patients not receiving the most appropriate therapy at recurrence. This paper proposes nine statements providing practical and concise advice on BRAF mutation testing in CRC, derived from collegial discussion and analysis of a multidisciplinary team of experts, including referral Italian oncologists and pathologists. The statements overview pivotal aspects implied in the detection, treatment and management of BRAF-mutated patients and have been drafted to represent a valuable tool for healthcare professionals committed to mCRC patient management. In addition, they represent a platform for implementing diagnostic-therapeutic workflows that can adapt to the variability of local resources while respecting the high-quality standards required by modern precision oncology., Competing Interests: Declaration of Competing Interest FB received personal honoraria as invited speaker from Eli-Lilly, MSD, EISAI, Bristol Myers Squibb, AstraZeneca, Pierre Fabre; participation in advisory board for Servier, AAA Novartis. CC reported the following: advisory board or consultant role with Astra Zeneca, Merck Serono, MSD, Nordic Pharma, Roche, Pierre Fabre, Takeda, Tempus; invited speaker with compensation for Amgen, Bayer, Merck Serono, MSD, Pierre Fabre Servier, Takeda; Research grants by Amgen, Merck, Pierre Fabre, Roche, Seagen (Pfizer), Servier, Tempus. MF reported the following: advisory board or consultant role with Amgen, Astellas, Astra Zeneca, BMS, Sanofi, Diapath, Eli Lilly, GSK, Incyte, IQvia, Janssen Pharma, MSD, Novartis, Pierre Fabre, Roche; Research Funding (To Institution): Astellas, Diaceutics, Roche. FG reported the following: ADVISORY BOARDS: - MSD; GSK; Beigene; LECTURE FEES: Pierre Fabre; MSD; GSK; AAA; Novartis; Servier; Astellas; Incyte; BMS; AstraZeneca; BeiGene; Daiichi-Sankyo. EGR, outside the submitted work, has received advisory fees, honoraria, travel accommodation/expenses, grants and/or non-financial support from AstraZeneca, Exact Sciences, GSK, Illumina, MSD, Novartis, Roche, Sophia Genetics and Thermo Fisher Scientific; receipt of honoraria or consultation fees for speaker, consultancy or advisory roles: Amgen, Bayer, Eisai, Merck Serono, Pierre Fabre, Roche, Servier, Incyte, ESMO, MSD, Takeda; travel grant: AstraZeneca, Pierre Fabre,Bayer. RI reports consulting or advisory role for Pierre-Fabre and Bayer. TPL state no conflict of interest and have received no payment in the preparation of this manuscript. TPL reports receipt of honoraria or consultation fees for speaker, consultancy or advisory roles: Bayer, Pierre Fabre, Servier, Takeda. SL reports: consulting or Advisory Role from Amgen, Astellas, Astra Zeneca, Bayer Bristol-Myers Squibb, Daiichi-Sankyo, GSK, Incyte, Lilly, Merck Serono, MSD, Servier, Takeda, Rottapharm, Beigene; speakers' Bureau: Amgen, Astra Zeneca, Bristol-Myers Squibb, Incyte, GSK, Lilly, Merck Serono, MSD, Pierre-Fabre, Roche, Servier; Research Funding (To Institution): Amgen, Astellas, Astra Zeneca, Bayer, Bristol-Myers Squibb, Daichii Sankyo, Hutchinson, Incyte, Merck Serono, Mirati, MSD, Pfizer, Roche, Servier. UM has served as consultant and/or speaker bureau for Boehringer Ingelheim, Roche, MSD, Amgen, Thermo Fisher Scientifics, Eli Lilly, Diatech, GSK, Merck, AstraZeneca, Menarini Steamline, outside the current work. EM reported receiving honoraria or consultation fees for speaker, consultancy or advisory roles from Amgen, Bayer, Eisai, Merck Serono, Pierre Fabre, Roche, Servier, Incyte, ESMO, MSD, Takeda; travel grant: AstraZeneca, Pierre Fabre, Bayer. NN reports: Personal financial interests (speaker’s fee and/or advisory boards): MSD, Bayer, Biocartis, Illumina, Incyte, Roche, BMS, MERCK, Thermofisher, Astrazeneca, Eli Lilly, Novartis, Servier; Institutional financial interests (financial support to research projects): MERCK, Thermofisher, QIAGEN, Roche, Astrazeneca, Biocartis, Illumina; Non-financial interests: President, International Quality Network for Pathology (IQN Path); Past President, Italian Cancer Society (SIC); Scientific Director, IRST “Dino Amadori”, Forlì. PP received personal fees from MSD, Pierre-Fabre, Servier, Astellas, Incyte, AstraZeneca, GSK, Pharmacogenetics, BeiGene, Bristol-Myers Squibb, Lilly. AP reported consulting or advisory role for Daiichi, Beigene, Pierre-Fabre, Merck, Amgen, Bayer, Servier. FP reported receiving institutional research grants from BMS, Incyte, Agenus, Amgen, Lilly and AstraZeneca, and personal fees from BMS, MSD, Amgen, Merck-Serono, Pierre-Fabre, Servier, Bayer, Takeda, Astellas, Johnson&Johnson, Rottapharm, Ipsen, AstraZeneca, GSK, Daiichi-Sankyo, Seagen/Pfizer, Beigene. LS is currently supported by the Associazione Italiana per la Ricerca sul Cancro (AIRC) under My First Grant (MFAG) No. MFAG27367. LS reports consulting or advisory role for Pierre-Fabre, AstraZeneca, Bayer, SERVIER, Merck, Amgen, GSK, Incyte, Leopharma, MSD, Takeda. VA, FP reports no conflict of interest., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

The diagnosis of synchronous carcinomas, involving both the endometrium and ovaries, is not a rare finding in gynecologic pathology and represents a challenge with implications on tumor staging and therapeutic decision-making. A mono-institutional series of 11 metastatic and 6 paired synchronous endometrial and ovarian carcinomas were reviewed by 2 expert pathologists based on previously published histopathologic criteria. The series was investigated for DNA mismatch repair proteins, p53, and POLE status and was subject to DNA-based next-generation sequencing targeting 67 cancer-related genes. Out of 17 pairs, 16 featured the same histotype (10 endometrioid, 4 serous high-grade, and 2 clear cells). By using WHO 2020 criteria, 11 couples of tumors were confirmed as metastatic and 6 couples were confirmed as independent. Based on next-generation sequencing analysis, 16 of 17 cases (11 metastatic and 5 independent) of our series showed evidence of a clonal relationship between endometrial and ovarian carcinomas. In metastatic cases, the adverse outcome was associated with nonendometrioid/high-grade endometrioid histotype and with the p53-abnormal molecular subtype. Four cases originally fulfilling clinicopathological criteria of independent endometrial and ovarian carcinomas were clonally related, low-grade endometrioid histotype and POLE -mut, mismatch repair deficient, and no specific molecular profile molecular subtypes; no adverse event was recorded in this group. In summary, the molecular characterization of synchronous gynecologic carcinomas confirms their clonal origin in most cases. However, the results of our study point out that the clinical behavior of these tumors seems to be determined by the presence of high-risk WHO 2020 histologic criteria and molecular features (i.e. p53-abnormal), rather than the monoclonal origin., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 by the International Society of Gynecological Pathologists.)

Mismatch repair (MMR) immunohistochemical (IHC) evaluation has entered pathology routine practice as the first-line screening method to identify patients with MMR deficient (MMRd)/microsatellite instability (MSI) colorectal cancer (CRC), and its misdiagnosis may significantly impact the personalization of CRC patient care. To determine the prevalence of MMR protein intratumor heterogeneity in real-world practice, we collected a series of 8282 CRCs tested for MMR proteins in the setting of Lynch syndrome universal screening. Four heterogenous cases were also investigated for tumor infiltrating lymphocytes count, MSI status, and consensus molecular subtypes by Nanostring nCounter® Platform. Overall, 1056 (12.8%) CRCs showed a MMR altered status, with 46 cases showing a heterogeneous MMR profile (0.56% of the total, and 4.36% of all MMRd cases). To conclude, the authors make some critical remarks regarding the approach to MMR heterogeneity in clinical practice and routine diagnostics., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: High-grade gastro-entero-pancreatic neoplasms (HG GEP-NENs) can be stratified according to their morphology and Ki-67 values into three prognostic classes: neuroendocrine tumors grade 3 (NETs G3), neuroendocrine carcinomas with Ki-67 < 55% (NECs <55) and NECs with Ki-67 ≥ 55% (NECs ≥55)., Methods: We analyzed a cohort of 49 HG GEP-NENs by targeted Next-Generation Sequencing (TrueSight Oncology 500), RNA-seq, and immunohistochemistry for p53, Rb1, SSTR-2A, and PD-L1., Results: Frequent genomic alterations affected TP53 (26%), APC (20%), KRAS and MEN1 (both 11%) genes. NET G3 were enriched in MEN1 (p = 0.02) mutations, while both NECs groups were enriched in TP53 (p = 0.001), APC (p = 0.002) and KRAS (p = 0.02) mutations and tumors with TMB ≥ 10 muts/Mb (p = 0.01). No differentially expressed (DE) gene was found between NECs <55% and NECs ≥55%, while 1129 DE genes were identified between NET G3 and NECs. A slight enrichment of CD4 + and CD8 + T cells in NECs and of cancer-associated fibroblasts and macrophages (M2-like) in NET G3. Multivariate analysis identified histologic type and Rb1 loss as independent prognostic factors for overall survival., Conclusions: This study showed that GEP-NET G3 and GEP-NECs exhibit clear genomic and transcriptomic differences, differently from GEP-NECs <55% and GEP-NECs ≥55%, and provided molecular findings with prognostic and potentially predictive value., (© 2024. The Author(s).)

Patients with autoimmune gastritis (AIG) have a 13-fold risk of developing type-1 neuroendocrine tumors, whereas the risk for gastric adenocarcinoma is still uncertain. Here we describe the clinicopathologic and molecular features of a series of gastric carcinomas (GC) arising in the context of AIG. A total of 26 AIG-associated GC specimens were collected from 4 Italian Institutions. Immunohistochemistry for MUC1, MUC2, MUC5AC, MUC6, CDX2, HER2, PD-L1, CLDN18, mismatch repair (MMR) proteins, and p53 and EBV-encoded RNA (EBER) in situ hybridization were performed. Histologic and immunohistochemical features were jointly reviewed by 5 expert gastrointestinal pathologists. Next-generation sequencing analysis (TrueSight Oncology 500, Illumina) of 523 cancer-related genes was performed on 19 cases. Most tumors were diagnosed as pT1 (52%) and they were located in the corpus/fundus (58%) and associated with operative link for gastritis assessment stage II gastritis (80.8%), absence of parietal cells, complete intestinal metaplasia, and enterochromaffin-like-cell micronodular hyperplasia. Only 4 (15.4%) GCs were diagnosed during follow-up for AIG. The following histotypes were identified: 20 (77%) adenocarcinomas; 3 (11%) mixed neuroendocrine-non-neuroendocrine neoplasms, and 2 (8%) high-grade solid adenocarcinomas with focal neuroendocrine component, 1 (4%) adenocarcinoma with an amphicrine component. Overall, 7 cases (27%) showed MMR deficiency, 3 (12%) were positive (score 3+) for HER2, 6 (23%) were CLDN18 positive, and 11 (42%) had PD-L1 combined positive score ≥ 10. EBER was negative in all cases. Molecular analysis revealed 5/19 (26%) microsatellite instability (MSI) cases and 7 (37%) tumor mutational burden (TMB) high. The most frequently altered genes were TP53 (8/19, 42%), RNF43 (7/19, 37%), ERBB2 (7/19, 37% [2 amplified and 5 mutated cases]), ARID1A (6/19, 32%), and PIK3CA (4/19, 21%). In summary, AIG-associated GCs are often diagnosed at low stage in patients with longstanding misrecognized severe AIG; they often display a neuroendocrine component or differentiation, have relatively higher rates of MMR deficiency, and TMB high., (Copyright © 2024 United States & Canadian Academy of Pathology. Published by Elsevier Inc. All rights reserved.)

Purpose: The multi-kinase inhibitor (mKi) regorafenib has demonstrated efficacy in chemorefractory patients with metastatic colorectal cancer (mCRC). However, lack of predictive biomarkers and concerns over significant toxicities hamper the use of regorafenib in clinical practice., Experimental Design: Serial liquid biopsies were obtained at baseline and monthly until disease progression in chemorefractory patients with mCRC treated with regorafenib in a phase II clinical trial (PROSPECT-R n = 40; NCT03010722) and in a multicentric validation cohort (n = 241). Tissue biopsies collected at baseline, after 2 months and at progression in the PROSPECT-R trial were used to establish patient-derived organoids (PDO) and for molecular analyses. MicroRNA profiling was performed on baseline bloods using the NanoString nCounter platform and results were validated by digital-droplet PCR and/or ISH in paired liquid and tissue biopsies. PDOs co-cultures and PDO-xenotransplants were generated for functional analyses., Results: Large-scale microRNA expression analysis in longitudinal matched liquid and tissue biopsies from the PROSPECT-R trial identified MIR652-3p as a biomarker of clinical benefit to regorafenib. These findings were confirmed in an independent validation cohort and in a "control" group of 100 patients treated with lonsurf. Using ex vivo co-culture assays paired with single-cell RNA-sequencing of PDO established pre- and post-treatment, we modeled regorafenib response observed in vivo and in patients, and showed that MIR652-3p controls resistance to regorafenib by impairing regorafenib-induced lethal autophagy and by orchestrating the switch from neo-angiogenesis to vessel co-option., Conclusions: Our results identify MIR652-3p as a potential biomarker and as a driver of cell and non-cell-autonomous mechanisms of resistance to regorafenib., (©2024 American Association for Cancer Research.)

Background: Little is known about prognostic factors of brain metastases (BM) from colorectal cancer (CRC). HER2 amplification/overexpression (HER2+) was previously described; its impact on prognosis remains uncertain., Methods: In the translational study HEROES, extensive molecular analysis was performed on primary CRC (prCRC) and their matched resected BM by means of NGS comprehensive genomic profiling and HER2 status as assessed by immunohistochemical/ in situ hybridization. Count of tumour-infiltrating lymphocytes (TILs) was also performed., Primary Objective: to describe the molecular landscape of paired BM/prCRC., Secondary Objectives: to search for new prognostic biomarkers of outcome after BM resection: intracranial-only Progression-Free Survival (BM-iPFS), Progression-Free Survival (BM-PFS), and Overall Survival (BM-OS)., Results: Out of 22 patients having paired samples of prCRC and BM, HER2+ was found on 4 (18%) BM, 3 (75%) of which also HER2+ in matched prCRC. Lower tumour mutation burden (HR 3.08; 95%CI 1.06-8.93; p = 0.0386) and HER2-negative BM (HER2neg) (HR 7.75;95%CI 1.97-30.40; p = 0.0033) were associated with longer BM-iPFS; HER2neg BM (HR 3.44; 95%CI 1.03-11.53; p = 0.0449) and KRAS mut BM (HR 0.31; 95%CI 0.12-0.80; p = 0.0153) conferred longer BM-PFS. Longer BM-OS was found in pts with TILs-enriched (≥1.6/HPF) BM (HR 0.11; 95%CI0.01-0.91; p = 0.0403)., Conclusions: This study shows HER2+ enrichment in both BM and their prCRC. TILs-enriched BM conferred better BM-OS., (© 2024. The Author(s).)

Biliary tract cancers (BTCs) represent a spectrum of malignancies associated with a dismal prognosis. Recent genomic profiling studies have provided a deeper understanding of the complex and heterogenous molecular landscape of BTCs, identifying several actionable genetic alterations, and expanding treatment options. Due to the high number and complexity of genetic alterations which require testing, next-generation sequencing (NGS) is currently the preferred approach over conventional methods (i.e., immunohistochemistry, fluorescence in-situ hybridization and PCR) for molecular profiling of BTCs and should be performed upfront in all BTC patients. However, BTC sampling often yields low tumor cellularity tissue, hampering NGS analysis. Future perspectives to overcome this obstacle include liquid biopsy and optimization of biopsy protocols. In this position paper, the authors discuss the current histopathologic, molecular, and therapeutic landscape of BTCs, provide a critical overview of the available testing methods for molecular diagnostics, and propose a practical diagnostic algorithm for molecular testing of BTC samples., Competing Interests: Declaration of Competing Interest All other authors declare that they have no conflict of interest related to the present work. Conflict of interest statement MF has been involved in consulting/advisory roles in Astellas Pharma, Pierre Fabre, MSD, AstraZeneca, Janssen, GlaxoSmithKline, BMS, Incyte, Amgen, Novartis and Roche, and received research funding from Astellas Pharma, QED Therapeutics, Diaceutics and Macrophage Pharma. NN has been involved in consulting/advisory roles in MSD, Bayer, Biocartis, Illumina, Incyte, Roche, BMS, Merck, Thermofisher, AstraZeneca, Eli Lilly, Novartis; financial support to research projects (institutional grants) from Merck, Thermofisher, QIAGEN, Roche, AstraZeneca, Biocartis, Illumina, Sophia genetics; non-financial interests President of the International Quality Network for Pathology (IQN Path) and Past President of the Italian Cancer Society (SIC). GP has been involved in consulting/advisory roles in Roche, Illumina, Novartis, Lilly, AstraZeneca, Exact Sciences, ADS Biotech. GT has received honoraria from Molteni, Novartis and Pharmamar. AS has received consulting fees from Amgen, AstraZeneca, Basilea, Incyte, and Ipsen and lecture fees from Amgen, Incyte, Ipsen, Merck Serono, Roche, and Sanofi. LR has received consulting fees from AstraZeneca, Basilea, Bayer, BMS, Eisai, Exelixis, Genenta, Hengrui, Incyte, Ipsen, IQVIA, Jazz Pharmaceuticals, MSD, Nerviano Medical Sciences, Roche, Servier, Taiho Oncology, and Zymeworks; lecture fees from AstraZeneca, Bayer, BMS, Eisai, Incyte, Ipsen, Merck Serono, Roche, and Servier; travel expenses from AstraZeneca; and institutional research funding from Agios, AstraZeneca, BeiGene, Eisai, Exelixis, Fibrogen, Incyte, Ipsen, Lilly, MSD, Nerviano Medical Sciences, Roche, and Zymeworks. FG has been involved in consulting/advisory roles in MSD and GlaxoSmithKline; lecture fees from MSD, Incyte and GlaxoSmithKline., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Aims: Very early-onset inflammatory bowel disease (VEO-IBD) is a clinical umbrella term referring to IBD-like symptoms arising in children before the age of 6 years, encompassing both 'pure' IBD, such as ulcerative colitis (UC) and Crohn's disease (CD) and monogenic diseases (MDs), the latter often involving genes associated with primary immunodeficiencies. Moreover, histological features in gastrointestinal (GI) biopsies in MD can also have IBD-like morphology, making differential diagnosis difficult. Correct diagnosis is fundamental, as MDs show a more severe clinical course and their inadequate/untimely recognition leads to inappropriate therapy., Methods and Results: Biopsy samples from the lower and upper GI tract of 93 clinically diagnosed VEO-IBD children were retrospectively selected in a multicentre cohort and histologically re-evaluated by 10 pathologists blinded to clinical information. Each case was classified according to morphological patterns, including UC-like; CD-like; enterocolitis-like; apoptotic; eosinophil-rich; and IBD-unclassified (IBD-U). Nine (69%) MD children showed IBD-like morphology; only the IBD-U pattern correlated with MD diagnosis (P = 0.02) (available in 64 cases: 51 non-MD, true early-onset IBD/other; 13 MD cases). MD patients showed earlier GI symptom onset (18.7 versus 26.9 months) and were sent to endoscopy earlier (22 versus 37 months), these differences were statistically significant (P < 0.05). Upper GI histology was informative in 37 biopsies., Conclusions: The diagnosis of the underlying cause of VEO-IBD requires a multidisciplinary setting, and pathology, while being one of the fundamental puzzle pieces, is often difficult to interpret. A pattern-based histological approach is therefore suggested, thus aiding the pathologist in VEO-IBD reporting and multidisciplinary discussion., (© 2023 The Authors. Histopathology published by John Wiley & Sons Ltd.)

Claudin-18.2 (CLDN18.2) is a member of the tight junction protein family and is a highly selective biomarker with frequent abnormal expression during the occurrence and development of various primary malignant tumors, including gastric cancer (GC) and esophago-gastric junction adenocarcinomas (EGJA). For these reasons, CLDN18.2 has been investigated as a therapeutic target for GC/EGJA malignancies. Recently, zolbetuximab has been proposed as a new standard of care for patients with CLDN18.2-positive, HER2-negative, locally advanced and metastatic GC/EGJA. The use of CLDN18 IHC assays to select patients who might benefit from anti-CLDN18.2 therapy is currently entering clinical practice. In this setting, pathologists play a central role in therapeutic decision-making. Accurate biomarker assessment is essential to ensure the best therapeutic option for patients. In the present review, we provide a comprehensive overview of available evidence on CLDN18.2 testing and its impact on the therapeutic management of patients with GC/EGJA, as well as some practical suggestions for CLDN18.2 staining interpretation and potential pitfalls in the real-world setting., Competing Interests: Declaration of Competing Interest FP received honoraria from BMS, MSD, Merck-Serono, Amgen, Takeda, Bayer, Servier, Astellas, Pierre-Fabre; research grants from Agenus, Amgen, Astrazeneca, Incyte, BMS. SL had roles as consultant or advisor for Amgen, Astra Zeneca, Bristol-Myers Squibb, Daiichi-Sankyo, Incyte, Lilly, Merck Serono, MSD, Servier, she received research funding from Amgen, Astellas, Astra-Zeneca, Bayer, BMS Daichii Sankyo, Hutchinson, Incyte, Merck Serono, Mirati, MSD, Pfizer, Roche and she is part of speakers’ bureau of Amgen, Bristol-Myers Squibb, GlaxoSmithKline, Lilly, Merck Serono, Pierre Fabre, Roche, Servier. MF had roles as consultant or advisor for Amgen, Astra Zeneca, Bristol-Myers Squibb, Incyte, Lilly, MSD, Astellas, GlaxoSmithKline, Roche, Pierre Fabre, he received research funding from Astellas, QED, Macrophage pharma, Diaceutics. FG has advisory board roles for GlaxoSmithKline and MSD, speakers honoraria from MSD, GlaxoSmithKline, Pierre Fabbre, Incyte., (Copyright © 2024 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Introduction: Immune-related adverse events (irAEs) constitute a challenge in the clinical management of solid tumors. This study aims to collect real-world data on the occurrence of immune-mediated diarrhea and colitis (IMDC) in advanced non-small cell lung cancer (aNSCLC) treated with immune checkpoint inhibitors (ICIs) and to assess the clinical impact of a multidisciplinary approach (MDA) on IMDC management., Methods: We retrospectively collected data on patients with aNSCLC consecutively treated with ICIs, either as single agent or in combination with chemotherapy, between September 2013 and July 2022. Among patients developing IMDC, we conducted blinded revision of colonic biopsies and evaluated the clinical impact of the introduction of MDA through predefined indicators., Results: Among the 607 patients included, 84 (13.8%) experienced IMDC. Pathological review highlighted a high prevalence of microscopic colitis (28%), with a collagenous pattern linked to longer symptoms duration (P = .01). IMDC occurred more frequently in females (P = .05) and PD-L1 expressors (P = .014) and was correlated with longer progression-free survival (17.0 vs 5.8, P < .001) and overall survival (28.3 vs 9.5, P < .001). The introduction of MDA was associated with increased employment of diagnostical tools such as fecal calprotectin test (P < .001), colonoscopy (P < .001), and gastroenterological evaluation (P = .017) and a significant decrease in both grade 3 conversion rate (P = .046) and recurrence after rechallenge (P = .016). Hospitalization rate dropped from 17.2% to 3.8% (P: ns)., Conclusion: These findings highlight the clinical relevance of IMDC and support the incorporation of a MDA to optimize the clinical management of this irAE to improve patient care. Prospective validation has been planned., (© The Author(s) 2023. Published by Oxford University Press.)

Aims: In the DESTINY-Gastric01 trial, a novel HER2-targeted antibody-drug conjugate trastuzumab deruxtecan proved to be effective in HER2-low gastro-oesophageal adenocarcinomas. The aim of our study is to investigate the clinicopathological and molecular features of HER2-low gastric/gastro-oesophageal junction cancers in the real-world setting of a large multi-Institutional series., Methods: We retrospectively evaluated 1210 formalin-fixed paraffin-embedded samples of gastro-oesophageal adenocarcinomas which were analysed by immunohistochemistry for HER2 protein expression in 8 Italian surgical pathology units from January 2018 to June 2022. We assessed the prevalence of HER2-low (ie, HER2 1+ and HER2 2+ without amplification) and its correlation with clinical and histopathological features, other biomarkers' status, including mismatch repair/microsatellite instability status, Epstein-Barr encoding region (EBER) and PD-L1 Combined Positive Score., Results: HER2 status could be assessed in 1189/1210 cases, including 710 HER2 0 cases, 217 HER2 1+, 120 not amplified HER2 2+, 41 amplified HER2 2+ and 101 HER2 3+. The estimated prevalence of HER2-low was 28.3% (95% CI 25.8% to 31.0%) overall, and was higher in biopsy specimens (34.9%, 95% CI 31.2% to 38.8%) compared with surgical resection specimens (21.0%, 95% CI 17.7% to 24.6%) (p<0.0001). Moreover, HER2-low prevalence ranged from 19.1% to 40.6% among centres (p=0.0005)., Conclusions: This work shows how the expansion of the HER2 spectrum might raise problems in reproducibility, especially in biopsy specimens, decreasing interlaboratory and interobserver concordance. If controlled trials confirm the promising activity of novel anti-HER2 agents in HER2-low gastro-oesophageal cancers, a shift in the interpretation of HER2 status may need to be pursued., Competing Interests: Competing interests: MF has been involved in consulting/advisory roles in Astellas Pharma, Pierre Fabre, MSD, GlaxoSmithKline, Amgen, Novartis and Roche, and received research funding from Astellas Pharma, QED Therapeutics, Diaceutics and Macrophage Pharma., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Refractory celiac disease (RCD) and enteropathy-associated T-cell lymphoma (EATL) are rare, yet severe complications of celiac disease (CD). Over the last decades, several studies have addressed the biology and clinical-pathological features of such conditions, highlighting unique disease patterns and recurrent genetic events. Current classification proposals identify two forms of RCD, namely: (i) type 1 RCD (RCD-I), characterized by phenotypically normal intra-epithelial lymphocytes (IELs); and (ii) type 2 RCD (RCD-II), featuring phenotypically aberrant IELs. While RCD-I likely represents a gluten-independent dysimmune reaction against small bowel epithelial cells, RCD-II is better considered an in situ aggressive T-cell lymphoma, with high rates of progression to overt EATL. The diagnosis of RCD and EATL is often challenging, due to misleading clinical-pathological features and to significant overlap with several CD-unrelated gastro-intestinal disorders. Similarly, the treatment of RCD and EATL is an unmet clinical need for both gastroenterologists and hematologists. Moving from such premises, this review aims to provide a comprehensive view of RCD and EATL, specifically considering their pathogenesis and the many still open issues concerning their diagnosis and clinical management., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Scarmozzino, Pizzi, Pelizzaro, Angerilli, Dei Tos, Piazza, Savarino, Zingone and Fassan.)

Background: Reliability of mismatch repair proteins and microsatellite instability assessment is essential in order to define treatment strategy and identify candidates to immune checkpoint inhibitors in locally advanced gastroesophageal carcinoma. We evaluated the concordance of deficient mismatch repair (dMMR) and microsatellite instability-high (MSI-H) status between endoscopic biopsies and surgical specimens., Methods: Consecutive patients with resectable gastric or gastroesophageal junction adenocarcinoma classified as MSI-H/dMMR by polymerase chain reaction (PCR) or immunohistochemistry (IHC) and operated at three referral Institutions were included. The primary endpoint was the rate of concordance between biopsy and surgical samples. If needed, central revision by IHC/PCR was performed by specialized pathologists from coordinating Institutions., Results: Thirteen (19.7%) out of 66 patients showed discordant MSI-H/dMMR results in the original pathology reports. In most cases (11, 16.7%) this was due to the diagnosis of proficient mismatch repair status on biopsies. Among the ten cases available for central review, four were due to sample issues, four were reclassified as dMMR, one case showed dMMR status but was classified as microsatellite stable by PCR, one was linked to misdiagnosis of endoscopic biopsy by the local pathologist. Heterogeneity of mismatch repair proteins staining was observed in two cases., Conclusions: Available methods can lead to conflicting results in MSI-H/dMMR evaluation between endoscopic biopsies and surgical samples of gastroesophageal adenocarcinoma. Strategies aiming to improve the reliability of assessment should be primarily focused on the optimization of tissue collection and management during endoscopy and adequate training of dedicated gastrointestinal pathologists within the multidisciplinary team., (© 2023. The Author(s) under exclusive licence to The International Gastric Cancer Association and The Japanese Gastric Cancer Association.)

Mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) are epithelial neoplasms in which neuroendocrine and non-neuroendocrine discrete components are combined, each of which constitutes ≥ 30% of the neoplasm. The finding of an additional neuroendocrine component seems to characterize the tumor's biological behavior. Few studies have proved MiNENs histogenetic and molecular characterization, and the development of molecular markers for more accurate classification of MiNENs represents a clinical need. However, a common origin of the neuroendocrine and non-neuroendocrine components from a pluripotent cancer stem cell could be suggested. The optimal clinical management of MiNENS is largely unknown. Whenever feasible, curative-intent resection should be performed for localized disease; in advanced disease, the treatment should be targeted to the component responsible for the metastatic spreading. This paper provides a revision of the current knowledge on MiNENs, focusing on available evidence about their molecular characterization to suggest a prognostic stratification of these rare forms., Competing Interests: Declaration of Competing Interest None of the authors declared a conflict of interests related to the present work., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Aims: Mucinous adenocarcinoma (MA) is associated with a high frequency of microsatellite instability (MSI). In the metastatic setting, it is crucial to establish mismatch repair (MMR) and/or MSI status. However, genetic heterogeneity between primary tumour and synchronous metastasis and the diagnostic accuracy of the assay may hamper the MMR/MSI status evaluation., Methods: In this study, we assessed the concordance rate of the MMR/MSI status between primary tumour and paired synchronous metastasis of 25 MAs. MMR status was evaluated by immunohistochemistry (IHC), while MSI status was evaluated by using three different molecular approaches: microfluidic electrophoresis of PCR products (TapeStation 4200 platform), full-closed RTqPCR system (Idylla system) and multiplex amplification with fluorescent primers and subsequent DNA fragment analysis on an automated sequencer (Titano MSI test)., Results: The concordance rate between primary MA and metastasis was 21/21 (100%), 23/25 (92.0%), 23/25 (92.0%) and 21/25 (84%) by using IHC, Idylla system, Titano MSI test and TapeStation 4200 system. All the four methods used in our study displayed high concordant rate, ranging from 91.0% (IHC vs Tapestation 4200 platform) to 98.0% (IHC vs Titano)., Conclusions: Several methodologies are frequently adopted in routine practice to successfully perform MMR/MSI status analysis. The most relevant issues related to MMR/MSI status analysis in MAs concern with low percentage of neoplastic cell and abundant mucine that may affect the molecular analysis. Thus, it might be useful to acquire both primary and metastatic sample to evaluate the MMR/MSI status by integrating IHC evaluation and molecular methodologies to successfully perform molecular profiling for MA patients., Competing Interests: Competing interests: UM has received personal fees (as consultant and/or speaker bureau) from Boehringer Ingelheim, Roche, MSD, Amgen, Thermo Fisher Scientifics, Eli Lilly, Diaceutics, GSK, Merck and AstraZeneca, unrelated to the current work. GT reports personal fees (as speaker bureau or advisor) from Roche, MSD, Pfizer, Boehringer Ingelheim, Eli Lilly, BMS, GSK, Menarini, AstraZeneca, Amgen and Bayer, unrelated to the current work. SL reports personal fees (as speaker bureau or advisor) from Amgen, Merck Serono, Lilly, Astra Zeneca, Incyte, Daiichi-Sankyo, Bristol-Myers Squibb, Servier, MSD, Roche, Bristol-Myers Squibb, Pierre-Fabre, GSK and received research grants from Amgen, Merck Serono, Bayer, Roche, Lilly, Astra Zeneca, Bristol-Myers Squibb, unrelated to the current work. MF reports personal fees (as speaker bureau or advisor) from Roche, MSD, GSK, Astellas Pharma, Diaceutics and received research grants from Astellas Pharma, QED therapeutics and macrophage pharma, unrelated to the current work., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

RAS gene mutational status represents an imperative predictive biomarker to be tested in the clinical management of metastatic colorectal adenocarcinoma. Even if it is one of the most studied biomarkers in the era of precision medicine, several pre-analytical and analytical factors may still impasse an adequate reporting of RAS status in clinical practice, with significant therapeutic consequences. Thus, pathologists should be aware on the main topics related to this molecular evaluation: (i) adopt diagnostic limit of detections adequate to avoid the interference of sub-clonal cancer cell populations; (ii) choose the most adequate diagnostic strategy according to the available sample and its qualification for molecular testing; (iii) provide all the information regarding the mutation detected, since many RAS mutation-specific targeted therapeutic approaches are in development and will enter into routine clinical practice. In this review, we give a comprehensive description of the current scenario about RAS gene mutational testing in the clinic focusing on the pathologist's role in patient selection for targeted therapies., (Copyright © 2023 Società Italiana di Anatomia Patologica e Citopatologia Diagnostica, Divisione Italiana della International Academy of Pathology.)

Colorectal adenosquamous carcinoma (ASC) is exceedingly rare, comprising less than 0.1% of all colorectal malignancies, and is characterized by an aggressive disease course, with a higher metastatic rate and worse outcome than conventional colorectal adenocarcinoma. A comprehensive molecular profile of this group of neoplasms is still lacking. A total of 22 cases of colorectal ASCs (with 22 primary lesions and 7 metastases matched with 4 primaries) were subject to NGS targeting 67 cancer-related genes (VariantPlex solid tumor; Archer). Mismatch repair (MMR), p53, and V600E BRAF status were also investigated by immunohistochemistry. In 28 of 29 (96.6%) ASC samples, at least one single-nucleotide variant (SNV) or copy number variation (CNV) was detected. Among the 22 primary tumors, the most frequently mutated genes were TP53 (59.1%), APC (40.9%), KRAS (27.3%), BRAF (13.6%), and GNAS (9.1%). Only 1/22 (4.5%) primary ASC was MMR-deficient (MMRd) and harbored a BRAF mutation. Limited differences in SNVs were observed between primary and metastatic diseases. This study sheds light on the molecular landscape of colorectal ASCs. According to our data, the genomic profile of colorectal ASC is similar to that of conventional colorectal carcinoma, with significant druggable genetic alterations. Further studies are required to understand the more aggressive clinical behavior of this neoplasm., (© 2023. The Author(s).)

Objective: Preoperative upper gastrointestinal endoscopy (UGIE) and postoperative histopathological examination (HPE) of resected specimens are still controversial issues in bariatric surgery., Methods: A retrospective review of prospectively collected laparoscopic sleeve gastrectomies (SG) performed at our institution for morbid obesity was carried out. All patients underwent pre-operative UGIE with biopsy, post-operative HPE and conventional post-operative follow-up., Results: From January 2019 through January 2021 we performed a total of 501 laparoscopic SG. A total of 12 (2.4%) neoplasms were found, 2 evident at preoperative UGIE, 4 detected during operation, and 6 at HPE. Eight of these 12 cases had some malignant potential and 5 would not have been detected without HPE of the specimen. The most significant unexpected case was a fundic gland type adenocarcinoma in a 64-year-old female with severe obesity., Conclusion: On the basis of our clinical experience, we recommend both preoperative endoscopic assessment and postoperative HPE of the specimen to provide the best available treatment to these patients., (Copyright © 2023 Società Italiana di Anatomia Patologica e Citopatologia Diagnostica, Divisione Italiana della International Academy of Pathology.)

Cholangiocarcinoma (CCA) is a heterogeneous group of neoplasms burdened by a dismal prognosis. Several studies have investigated the genomic profile of CCA and identified numerous druggable genetic alterations, including FGFR2 fusions/rearrangements. Approximately 5-7% of CCAs and 10-20% of intrahepatic iCCAs harbor FGFR2 fusions. With the recent advent of FGFR-targeting therapies into clinical practice, a standardization of molecular testing for FGFR2 alterations in CCA will be necessary. In this review, we describe the technical aspects and challenges related to FGFR2 testing in routine practice, focusing on the comparison between Next-Generation Sequencing (NGS) and FISH assays, the best timing to perform the test, and on the role of liquid biopsy., (Copyright © 2023 Società Italiana di Anatomia Patologica e Citopatologia Diagnostica, Divisione Italiana della International Academy of Pathology.)

PD-L1 is an established predictive immunohistochemical biomarker of response to immune checkpoint inhibitors. At present, PD-L1 is routinely assessed on biopsy samples of advanced gastroesophageal cancer patients before initiating first-line treatment. However, PD-L1 is still a suboptimal biomarker, due to changing cut-off values and scoring systems, interobserver and interlaboratory variability., This practical illustrated review discusses the range of staining patterns of PD-L1 and the potential pitfalls and challenges that can be encountered when evaluating PD-L1, focusing on gastric and gastroesophageal adenocarcinoma (G/GEA) and esophageal squamous cell carcinoma (ESCC)., (Copyright © 2022 Società Italiana di Anatomia Patologica e Citopatologia Diagnostica, Divisione Italiana della International Academy of Pathology.)

Background: Approximately 15 % of colorectal adenocarcinomas (CRCs) are characterized by an altered expression of DNA mismatch repair (MMR) proteins (i.e. MMR deficiency [MMRd]). Lymph node ratio (LNR) represents one of the most important prognostic markers in non-advanced CRCs. No significant data are available regarding LNR distribution depending on MMR status., Purpose of the Study: The aim of the present work was to compare pathological and clinical characteristics of MMRd tumors versus MMR proficient (MMRp) cases. Particular attention was paid to how these molecular sub-groups relate to the LNR., Materials and Methods: A mono-Institutional series of 1037 consecutive surgically treated stage I-IV CRCs were retrospectively selected and data were obtained from pathological reports. Cases were characterized for MMR/MSI status by means of immunohistochemistry or for microsatellite instability (MSI) analysis., Results: MMRd/MSI tumors (n = 194; 18.7 %) showed significant differences in comparison to MMRp lesions for sex (female prevalence 50.5 % vs 40.7 %; p = 0.013), age (74.2 vs 69.2; p < 0.001), location (right side; p < 0.001), diameter (larger than MMRp; p < 0.001), growth pattern (expansive pattern of growth; p < 0.001), peri- (p = 0.0002) and intra-neoplastic (p = 0.0018) inflammatory infiltrate, presence of perineural invasion (p < 0.001), stage (lower stage at presentation; p < 0.001), grade (higher prevalence of high-grade tumors; p < 0.001), and LNR (lower; p < 0.001)., Conclusions: MMRd/MSI tumors are a distinct molecular CRC subtype characterized by a significantly lower LNR in comparison to MMRp lesions. These data further support the prognostic impact of MMRd/MSI status in early-stage CRCs., Competing Interests: Declaration of Competing Interest None related to the current work., (Copyright © 2023 Elsevier GmbH. All rights reserved.)

Background: Currently, preoperative staging of esophageal adenocarcinoma (EAC) has modest reliability and accuracy for pT and pN stages prediction, which heavily affects overall survival. The interplay among immune checkpoints, oncogenes, and intratumoral and peritumoral immune infiltrating cells could be used to predict loco-regional metastatic disease in early EAC., Methods: We prospectively evaluated immune markers expression and oncogenes status as well as intratumoral and peritumoral immune infiltrating cells populations in esophageal mucosa samples obtained from neoadjuvant therapy-naïve patients who had esophagectomy for EAC., Results: Vascular invasion and high infiltration of lamina propria mononuclear cells resulted associated with nodal metastasis. Low infiltration of activated CD8 + CD28 + T cells was observed in both intratumoral and peritumoral mucosa of patients with nodal metastasis. Low levels of CD69, MYD88, and TLR4 transcripts were detected in the intratumoral specimen of patients with lymph node involvement. Receiver operating characteristic curve analysis showed good accuracy for detecting nodal metastasis for all the markers tested. Significant lower infiltration of CD8 T cells and M1 macrophages and a lower expression of CD8A, CD8B, and TBX21 were found also in Esophageal Adenocarcinoma TCGA panCancer Atlas in the normal tissue of patients with nodal metastasis., Conclusions: Our data suggest that immune surveillance failure is the main driver of nodal metastasis onset. Moreover, nodal metastasis containment also involves the immune microenvironment of the peritumoral healthy tissue., (© 2022 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Background: Molecular characteristics of squamous cell anal carcinoma (SCAC) are poorly explored. Immune checkpoint inhibitors showed limited activity in phase I/II trials, but predictive and prognostic biomarkers are lacking., Patients and Methods: In the phase II randomised trial CARACAS (NCT03944252), avelumab alone (Arm A) or with cetuximab (Arm B) was tested in pre-treated advanced SCAC , with overall response rate being the primary end-point. On pre-treatment tumour tissue samples, we assessed Human papillomavirus status, programmed-death ligand 1 (PD-L1) expression, mismatch repair proteins expression, tumour mutational burden (TMB) and comprehensive genomic profiling by FoundationOne CDx. Tumour-infiltrating lymphocytes were characterised on haematoxylin-eosine-stained samples. Primary objective was to describe response to immunotherapy in the CARACAS trial population according to molecular and histological characteristics. Secondary objectives were to assess progression-free survival (PFS) and overall survival (OS) according to molecular biomarkers., Results: High PD-L1 (>40 with combined positive score) was significantly more frequent in patients with disease control (p = 0.0109). High TMB (>10 mutations per megabase) was related to better OS (hazard ratio (HR) = 0.09; 95%confidence interval (CI) 0.01-0.68; p = 0.019) and PFS (HR = 0.44; 95%CI = 0.15-1.27; p = 0.129). High expression of PD-L1 conferred longer OS (HR = 0.46; 95%CI = 0.19-1.08; p = 0.075) and PFS (HR = 0.42; 95%CI = 0.20-0.92; p = 0.03). Neither OS (HR = 1.30; 95%CI = 0.72-2.36; p = 0.39) or PFS (HR = 1.31; 95%CI = 0.74-2.31; p = 0.357) was affected by high (>1.2) Tumour-infiltrating lymphocytes count. High TMB and PD-L1identified patients were with significantly better OS (HR = 0.33; 95%CI = 0.13-0.81; p = 0.015) and PFS (HR = 0.48; 95%CI = 0.23-1.00; p = 0.015)., Conclusions: To our knowledge, TranslaCARACAS is the first study to document prognostic role of TMB and PD-L1 in advanced SCAC patients treated with immune checkpoint inhibitors., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The comprehensive molecular characterization of gastric and gastroesophageal junction adenocarcinomas has led to the improvement of targeted and more effective treatments. As a result, several biomarkers have been introduced into clinical practice and the implementation of innovative diagnostic tools is under study. Such assessments are mainly based on the evaluation of limited biopsy material in clinical practice. In this setting, the pathologist represents a key player in the selection of patients facilitating precision medicine approaches., (© 2022. The Author(s).)

Gastroesophageal adenocarcinoma is a challenging disease due to its poor prognosis and the presence of few therapeutic options. For these reasons, it is mandatory to identify the subgroup of patients who are at high risk for relapse after curative-intention surgery. In the last years, liquid biopsy has aroused great interest in cancer treatment for its feasibility and the possibility to capture tumor heterogeneity in a real-time way. In postoperative setting, the interest is directed to the identification of Minimal Residual Disease (MRD), defined as isolated or small cluster of cancer cells that residues after curative-intention surgery, and are undetectable by conventional radiological and clinical exams. This review wants to summarize current evidence on the use of liquid biopsy in gastroesophageal cancer, focusing on the detection of ctDNA in the postoperative setting and its potential role as a guide for treatment decision., (© 2022. Italian Society of Surgery (SIC).)

Background: Peritoneal dissemination represents a poor prognostic indicator in gastric cancer. Despite a comprehensive molecular characterization of this disease, no peritoneal dissemination-specific signature has been identified, limiting the tailoring of the surgical and oncological treatments. In this review, we outline the available literature focusing on the role of the different molecular pathways involved in the acquisition of peritoneal metastatic dissemination., Summary: According to our results, several molecular determinants are associated with peritoneal carcinomatosis and are involved in several cellular and molecular carcinogenetic processes. However, a comprehensive understanding of the complex molecular landscape of gastric carcinosis is still lacking., Key Messages: More efforts should be made toward the integration of molecular and histologic data to perform a risk prediction assessment of peritoneal dissemination based on molecular profiling and histological evaluation., (© 2022 S. Karger AG, Basel.)

Background: The DNA mismatch repair (MMR) system is a highly preserved protein complex recognizing short insertions, short deletions, and single base mismatches during DNA replication and recombination. MMR protein status is identified using immunohistochemistry. Deficit in one or more MMR proteins, configuring deficient MMR status (dMMR), leads to frameshift mutations particularly clustered in microsatellite repeats. Thus, microsatellite instability (MSI) is the epiphenomenon of dMMR. In colorectal cancer (CRC), MMR/MSI status is a biomarker with prognostic and predictive value of resistance to 5-fluorouracil and response to immune checkpoint inhibitor therapy., Summary: In this Review, we describe the challenges the practicing pathologist may face in relation to the assessment of MMR/MSI status and any open issues which still need to be addressed, focusing on pre-analytic issues, pitfalls in the interpretation, and technical aspects of the different assays., Key Messages: The current methods of detecting dMMR/MSI status have been optimized for CRCs, and whether these techniques can be applied to all tumor and specimen types is still not fully understood. Following the Food and Drug Administration (FDA), tissue/site agnostic drug approval of pembrolizumab for advanced/metastatic MSI tumors, MMR/MSI status in gastrointestinal tract is a common request from the oncologist. In this setting, several issues still need to be addressed, including criteria for sample adequacy., (© 2023 S. Karger AG, Basel.)

Background: Despite the important advances in research on neuroendocrine neoplasms of the gastro-entero-pancreatic tract, their precursor lesions are much less well known., Summary: This review analyzes the preneoplastic neuroendocrine lesions of the gastro-entero-pancreatic tract, by adopting a coherent anatomical benchmark. In particular, the settings in which neuroendocrine precursor lesions represent well-recognized pathophysiological and morphological entities (with eventual molecular correlates) have been distinguished from the ones in which the nature of preneoplastic changes is still obscure., Key Messages: The aim of the paper was to summarize what is known about precursor lesions of gastro-entero-pancreatic neuroendocrine tumors, with the goal of providing a useful tool for future research aimed at obtaining a fuller understanding of the underlying biology and early development of these diseases., (© 2022 S. Karger AG, Basel.)

Non-ampullary small bowel adenocarcinoma is a rare neoplasm with an ominous prognosis, whose incidence is higher in some chronic immuno-inflammatory conditions, such as coeliac and Crohn's disease. Recently, claudin 18.2, a transmembrane protein normally expressed in gastric mucosa, has been recognized as a novel pan-cancer therapeutic target, and several clinical trials with claudin-18-directed drugs have shown promising results on various gastrointestinal malignancies. This is the first study focusing on claudin-18 expression in small bowel adenocarcinomas. The immunohistochemical expression of claudin-18 (clone 43-14A) was assessed in 81 small bowel adenocarcinomas of diverse aetiologies and correlated with several clinico-pathologic features and patient survival. We found that 28% of adenocarcinomas were immunoreactive for claudin-18, with cutoff values of ≥1% at any intensity, while 6% of cancers showed immunoexpression of ≥75% with 2+/3+ score. Moreover, claudin-18 (≥1%) was positively associated with cytokeratin 7 (CK7) and MUC5AC expression, showing CK7+/MUC5AC+ carcinomas the highest rate of positive cases, whereas a negative correlation was found between claudin-18 and CDX2 expression. In addition, some cancer-adjacent dysplastic growths and foci of gastric-type metaplasia in Crohn's disease-associated cases showed claudin-18 immunoreactivity. Survival analysis showed a non-significant trend towards a worse cancer-specific survival for claudin-18-positive cases. A fraction of small bowel adenocarcinomas, mainly sporadic or Crohn's disease-associated, and often exhibiting a non-intestinal immunoprofile, expressed claudin-18, suggesting that claudin-18-directed targeted therapy is worth investigating in such cancers., (© 2022. The Author(s).)

In sessile serrated lesions (SSLs) with adenomatous dysplasia, the dysplastic component and the serrated component without dysplasia should be considered as part of the same lesion, classified as SSL with dysplasia. However, some of these lesions may actually represent collisions between a serrated polyp and a conventional adenoma. Further supporting the "collision theory", conventional adenomatous dysplasia may be found in association with hyperplastic polyps (HPs). In order to determine the molecular and biological landscape of conventional type dysplasia in serrated lesions, we collected 17 cases of colorectal serrated lesions with adenomatous dysplasia, classifying them as SSL with dysplasia (n = 10) or as mixed lesions comprising a HP component and a conventional adenomatous component (n = 7). We characterized the dysplastic and the non-dysplastic component of each lesion, after microdissection, through the targeted mutational analysis of 11 commonly altered genes in colorectal cancer (AKT1, APC, BRAF, CTNNB1, KIT, KRAS, NRAS, PDGFRA, PIK3CA, PTEN and TP53). We also characterized MMR and p53 status by immunohistochemistry. Overall, 14/17 (82.4 %) cases harbored a mutation in at least one of the two components. The most altered genes were BRAF in 10/17 (58.8 %) cases, APC in 2/17 (11.8 %) and TP53 in 4/17 (23.5 %). Among the SSL with dysplasia, the mutational profile was concordant between the two components in 7/10 (70 %) cases, while among the mixed lesions, the mutational profile was concordant in 1/7 (14.3 %). In all but two cases of SSL with dysplasia, MMR status was concordant between the two components of the serrated lesions. Our findings suggest that adenomatous dysplasia may develop in SSL as part of the serrated lesion, even if some SSL with dysplasia may actually be collision lesions. On the other hand, the polyps that are morphologically classifiable as mixed lesions composed of a HP and a conventional adenomatous component are more likely to be collision lesions., (Copyright © 2022 Elsevier GmbH. All rights reserved.)

Gastric adenocarcinoma has recently been classified into several subtypes on the basis of molecular profiling, which has been successfully reproduced by immunohistochemistry (IHC) and in situ hybridization (ISH). A series of 73 gastroesophageal dysplastic lesions (37 gastric dysplasia and 36 Barrett dysplasia; 44 low-grade dysplasia and 29 high-grade dysplasia) was investigated for mismatch repair proteins, E-cadherin, p53, and EBER status, to reproduce The Cancer Genome Atlas (TCGA) and Asian Cancer Research Group (ACRG) molecular clustering. Overall, the dysplastic lesions were classified as follows: according to TCGA classification, EBV, 0/73 (0%), MSI, 6/73 (8.2%), GS, 4/73 (5.5%), CIN, 63/73 (86.3%); according to ACRG molecular subtyping, MSI, 6/73 (8.2%), MSS/EMT, 4/73 (5.5%), MSS/TP53 - , 33/73 (45.2%), MSS/TP53 + , 30/73 (41.1%). A positive association was found between MSS/TP53 - and Barrett dysplasia (p = 0.0004), between MSS/TP53 + and LG dysplasia (p = 0.001) and between MSS/TP53 + and gastric dysplasia (p = 0.0018). Gastroesophageal dysplastic lesions proved to be heterogenous in terms of TCGA/ACRG classes, but with a different distribution from that of cancers, with no EBV-positive cases, an increasing presence of mismatch repair deficiency from low grade to high grade lesions, and a prevalence of p53 aberrations in Barrett dysplasia. The present study further demonstrated that gastroesophageal dysplastic lesions may be characterized by alterations in predictive/prognostic biomarkers, and this should be considered in routine diagnostic., (© 2022. The Author(s).)

Immune-checkpoint inhibitors targeting the PD-1/PD-L1 axis have brought significant clinical benefit in many solid cancer types, including gastrointestinal malignancies. However, it has been estimated that only 20-40% of patients respond to treatment. The pattern of expression and potential predictive value of PD-L1 as an immunohistochemical biomarker has been extensively studied in gastrointestinal neoplasms. Until now, its predictive value has been demonstrated, and is currently in use only in upper gastrointestinal malignancies (gastroesophageal adenocarcinoma and esophageal squamous cell carcinoma)., In this Review, we describe the technical aspects and challenges related to PD-L1 immunohistochemical assays, the current role of PD-L1 as a biomarker in clinical practice and we outline the main studies and clinical trials analyzing the prognostic and predictive value of PD-L1 in gastrointestinal cancers., (Copyright © 2022 Società Italiana di Anatomia Patologica e Citopatologia Diagnostica, Divisione Italiana della International Academy of Pathology.)

A majority of patients with metastatic colorectal cancer (mCRC) experience recurrence post curative-intent surgery. The addition of adjuvant chemotherapy has shown to provide limited survival benefits when applied to all patients. Therefore, a biomarker to assess molecular residual disease (MRD) accurately and guide treatment selection is highly desirable for high-risk patients. This feasibility study evaluated the prognostic value of a tissue comprehensive genomic profiling (CGP)-informed, personalized circulating tumor DNA (ctDNA) assay (FoundationOne®Tracker) (Foundation Medicine, Inc., Cambridge, MA, USA) by correlating MRD status with clinical outcomes. ctDNA analysis was performed retrospectively on plasma samples from 69 patients with resected mCRC obtained at the MRD and the follow-up time point. Tissue CGP identified potentially actionable alterations in 54% (37/69) of patients. MRD-positivity was significantly associated with lower disease-free survival (DFS) (HR: 4.97, 95% CI: 2.67−9.24, p < 0.0001) and overall survival (OS) (HR: 27.05, 95% CI: 3.60−203.46, p < 0.0001). Similarly, ctDNA positive status at the follow-up time point correlated with a marked reduction in DFS (HR: 8.78, 95% CI: 3.59−21.49, p < 0.0001) and OS (HR: 20.06, 95% CI: 2.51−160.25, p < 0.0001). The overall sensitivity and specificity at the follow-up time point were 69% and 100%, respectively. Our results indicate that MRD detection using the tissue CGP-informed ctDNA assay is prognostic of survival outcomes in patients with resected mCRC. The concurrent MRD detection and identification of actionable alterations has the potential to guide perioperative clinical decision-making., Competing Interests: S.L. has been involved in consulting/advisory roles in Amgen, Merck Serono, Lilly, Servier, AstraZeneca, Incyte, Daiichi, Sankyo, and Bristol Myers Squibb, received a speaker honorarium from Roche, Lilly, Bristol Myers Squibb, Servier, Merck Serono, Pierre Fabre, GlaxoSmithKline, and Amgen, and received research funding from Amgen, Merck Serono, Bayer, Roche, Lilly, AstraZeneca, and Bristol Myers Squibb. C.X., D.R.Z., R.M., A.F., O.G., E.R., and P.H. are employees of Foundation Medicine, a wholly owned subsidiary of Roche, and have an equity interest in Roche. S.S., H.-T.W., C.C.P., and M.M. are employees of Natera, Inc. with stocks or options to own stocks. A.A. is an employee at Natera, Inc. with stocks or options to own stocks, received travel/accommodations and expenses from Natera, Inc, and has been involved in a consulting/advisory role in Mission Bio and Notable Labs. F. L. has been involved in consulting/advisory roles in Amgen, Sanofi, Bayer, and Amal Therapeutics, received speaker honoraria from Roche, Sanofi, Bayer, and Amgen, received research funding from Roche, Merck Serono, Amgen, and Bayer, and received travel, accommodations, and expenses from Rocher, Amgen and Merck Serono. M.F. has been involved in consulting/advisory roles in Astellas Pharma, Tesaro, GlaxoSmithKline, Diaceutics, and Roche, and received research funding from Astellas Pharma, QED Therapeutics, and Macrophage Pharma. H.N., C.R., and V.A. declare no conflict of interest.