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Abstract Background Metastatic urothelial carcinoma (mUC) has a poor prognosis, despite recent therapeutic advancements. Prostaglandin Reductase 1 (PTGR1) is essential for activating acylfulvens, a promising class of drugs for treating a subset of urothelial carcinoma (UC) patients. The efficacy of acylfulvens depends on PTGR1 activity and defects in the nucleotide excision repair (NER) pathway, notably ERCC2 mutations present in 10–15% of bladder tumors. This study identifies patients eligible to be included in acylfulven clinical trials based on the presence of PTGR-1 by immunohistochemistry (IHC) staining, RNA expression level and mutations in the NER pathway. Additionally, it evaluates PTGR-1 expression as a prognostic biomarker. Methods Three PTGR-1 antibodies were tested in a kidney cancer cell line A498 and in tissues with known PTGR1 expression (liver, tonsils, pancreas, small intestine, etc.). Patients with untreated mUC receiving 1st line platinum from Dec. 2019 to Dec. 2021 in the Capital Region, Denmark, were included retrospectively. FFPE tumor samples were collected, and tissue microarrays (TMAs) were constructed. TMAs were stained with the best-performing PTGR1 antibody, RNA expression was analyzed using Nanostring nCounter PanCancer panel and gene mutations were assessed using a targeted genomic panel (TSO-500). Kaplan-Meier and multivariate Cox regression assessed overall survival and covariate impacts. Results The AB181131 PTGR1 antibody was the most reliable in validation tissues. Tumors from 71 mUC patients were used to construct the TMA, and 40% of tumors scored positive for PTGR1 by IHC staining. A normalized PTGR1 RNA cutoff at 2,550 normalized counts achieved an AUC of 0.9, defining 35 samples as positive with a sensitivity of 96% and specificity of 85% in relation to IHC-positivity. Differential expression showed a significant upregulation of PTGR1 RNA in PTGR1 IHC-positive cases. NER-deficiency and PTGR1 positivity (mutations in ERCC1, ERCC2, ERCC3, ERCC4) was seen in 9 patients (13%). Median overall survival was 16 months in the cohort. Overall survival (OS) analysis indicates that overexpression of PTGR1 RNA was associated with a reduced median OS (12 months vs. 25 months, p = 0.039, log-rank). Conclusion PTGR1 IHC staining pattern using the Abcam AB181131 antibody is highly correlated with PTGR1 RNA expression. 13% in our cohort were identified as NER deficient and PTGR1 positive. Lower levels of PTGR1 indicates better outcome in this cohort.

Immune checkpoint inhibitor therapy has dramatically improved survival in a significant subset of patients with several solid tumor types. Increasing the number of patients benefitting from this form of therapy is an important translational research goal. Correlations between the composition of the gut microbiome and response to immune checkpoint inhibitor therapy raised the possibility that direct modulation of the gut microbiome may significantly improve the clinical benefit of this treatment. Several lines of observations suggest that tumor-associated carbohydrates, including those recognized as blood group-related glycolipid antigens, such as the Forssman antigen, may be some of the key factors behind this clinical correlation. Such antigens are expressed in human cancer, humans often produce antibodies against those, and they can induce antibody directed cellular cytotoxicity. Importantly, these antibodies are often induced by antigens present in microbes of the gut. If identified, these antibodies could be boosted by appropriate vaccination techniques and thus enhance anti-tumor immunity with minimal side effects.

Introduction: Intraneural ganglions are benign and rare mucinous cysts that originate within peripheral nerves and typically can lead to symptoms and signs of peripheral neuropathy. The most common location is the peroneal nerve, and the second most common location is the ulnar nerve. Case Presentation: We present a case of a 53-year-old man who presented with increasing numbness in the ulnar aspect of the left hand and decreasing hand strength. MRI showed an intraneural ganglion, and as the patient had clinically progressive symptoms, a decision was made for surgical excision. The patient was symptom-free after the procedure and had no neurological deficits. Eighteen months later, the patient contacted us again as his symptoms had returned. A new MRI showed ganglion recurrence. Due to progressive clinical symptoms, another attempt was made to remove the ganglion surgically. Paraffin immunostains excluded other diagnoses like synovial cyst, posttraumatic neuronal cyst, Tarlov cyst, mesothelial cyst, and cystic lymphangioma. At follow-up 3 months postoperatively, the patient was symptom-free and had normal neurological findings. Conclusion: Intraneural ganglion should be considered as a differential diagnosis of a cystic mass close to a nerve. For surgery, we favor less radical methods, such as simple decompression.

Background: This prospective pilot study explored the potential of the innate immune system’s response to cancer-related immuno-stimulants as a predictive biomarker for Immune Checkpoint Inhibitor (ICI) effectiveness, using pembrolizumab-treated metastatic urothelial tract cancer (mUTC) patients as the study population. Methods: We included ten mUTC patients and assessed their innate immune responses before the first and second pembrolizumab cycles with the TruCulture® immunoassay. We also executed survival analysis and compared cytokine release. Results: R848-induced IFNα and HKCA-induced IL-10 values decreased in patients with disease progression (n = 7), while these values increased in non-progressing patients (n = 3), denoting a significant difference (p = 0.00192 and p = 0.00343, respectively). Further, an increased R848-induced IFNα response correlated with extended survival (log-rank p-value of 0.048). Conclusion: Our small study identified distinct immune response patterns following pembrolizumab’s first cycle in mUTC patients, hypothesizing the potential of an increased R848-induced IFNα response for improved survival outcomes. Further confirmatory studies are in progress.

Abstract Due to a demonstrated lack of DNA repair deficiencies, clear cell renal cell carcinoma (ccRCC) has not benefitted from targeted synthetic lethality-based therapies. We investigated whether nucleotide excision repair (NER) deficiency is present in an identifiable subset of ccRCC cases that would render those tumors sensitive to therapy targeting this specific DNA repair pathway aberration. We used functional assays that detect UV-induced 6–4 pyrimidine-pyrimidone photoproducts to quantify NER deficiency in ccRCC cell lines. We also measured sensitivity to irofulven, an experimental cancer therapeutic agent that specifically targets cells with inactivated transcription-coupled nucleotide excision repair (TC-NER). In order to detect NER deficiency in clinical biopsies, we assessed whole exome sequencing data for the presence of an NER deficiency associated mutational signature previously identified in ERCC2 mutant bladder cancer. Functional assays showed NER deficiency in ccRCC cells. Some cell lines showed irofulven sensitivity at a concentration that is well tolerated by patients. Prostaglandin reductase 1 (PTGR1), which activates irofulven, was also associated with this sensitivity. Next generation sequencing data of the cell lines showed NER deficiency-associated mutational signatures. A significant subset of ccRCC patients had the same signature and high PTGR1 expression. ccRCC cell line-based analysis showed that NER deficiency is likely present in this cancer type. Approximately 10% of ccRCC patients in the TCGA cohort showed mutational signatures consistent with ERCC2 inactivation associated NER deficiency and also substantial levels of PTGR1 expression. These patients may be responsive to irofulven, a previously abandoned anticancer agent that has minimal activity in NER-proficient cells.

Abstract To date, single-nucleotide polymorphisms (SNPs) have been the most intensively investigated class of polymorphisms in genome wide associations studies (GWAS), however, other classes such as insertion-deletion or multiple nucleotide length polymorphism (MNLPs) may also confer disease risk. Multiple reports have shown that the 5p15.33 prostate cancer risk region is a particularly strong expression quantitative trait locus (eQTL) for Iroquois Homeobox 4 (IRX4) transcripts. Here, we demonstrate using epigenome and genome editing that a biallelic (21 and 47 base pairs (bp)) MNLP is the causal variant regulating IRX4 transcript levels. In LNCaP prostate cancer cells (homozygous for the 21 bp short allele), a single copy knock-in of the 47 bp long allele potently alters the chromatin state, enabling de novo functional binding of the androgen receptor (AR) associated with increased chromatin accessibility, Histone 3 lysine 27 acetylation (H3K27ac), and ~3-fold upregulation of IRX4 expression. We further show that an MNLP is amongst the strongest candidate susceptibility variants at two additional prostate cancer risk loci. We estimated that at least 5% of prostate cancer risk loci could be explained by functional non-SNP causal variants, which may have broader implications for other cancers GWAS. More generally, our results underscore the importance of investigating other classes of inherited variation as causal mediators of human traits.

Chromosomal instability in cancer consists of dynamic changes to the number and structure of chromosomes1,2. The resulting diversity in somatic copy number alterations (SCNAs) may provide the variation necessary for tumour evolution1,3,4. Here we use multi-sample phasing and SCNA analysis of 1,421 samples from 394 tumours across 22 tumour types to show that continuous chromosomal instability results in pervasive SCNA heterogeneity. Parallel evolutionary events, which cause disruption in the same genes (such as BCL9, MCL1, ARNT (also known as HIF1B), TERT and MYC) within separate subclones, were present in 37% of tumours. Most recurrent losses probably occurred before whole-genome doubling, that was found as a clonal event in 49% of tumours. However, loss of heterozygosity at the human leukocyte antigen (HLA) locus and loss of chromosome 8p to a single haploid copy recurred at substantial subclonal frequencies, even in tumours with whole-genome doubling, indicating ongoing karyotype remodelling. Focal amplifications that affected chromosomes 1q21 (which encompasses BCL9, MCL1 and ARNT), 5p15.33 (TERT), 11q13.3 (CCND1), 19q12 (CCNE1) and 8q24.1 (MYC) were frequently subclonal yet appeared to be clonal within single samples. Analysis of an independent series of 1,024 metastatic samples revealed that 13 focal SCNAs were enriched in metastatic samples, including gains in chromosome 8q24.1 (encompassing MYC) in clear cell renal cell carcinoma and chromosome 11q13.3 (encompassing CCND1) in HER2+ breast cancer. Chromosomal instability may enable the continuous selection of SCNAs, which are established as ordered events that often occur in parallel, throughout tumour evolution.

Background Effective cooperation between B-cells and T-cells within the tumor microenvironment may lead to the regression of established tumors. B-cells and T-cells can recognize tumor antigens with exquisite specificity via their receptor complexes. Nevertheless, whether a diverse intratumoral B-cells and T-cell receptor (BCR, TCR) repertoire affects the tumor immune microenvironment (TIME) and clinical outcomes in patients treated with immunotherapy is unclear.Methods We extracted information on BCR and TCR repertoire diversity from large clinical datasets and measured the association between immune receptor diversity features, the TIME, and clinical outcomes of patients treated with anti-PD-1/PD-L1 immunotherapy.Results In multiple tumor types, an increasingly diverse TCR repertoire was strongly associated with a highly activated TIME, while BCR diversity was more associated with antibody responses but not with the overall B-cell infiltration nor with measures related to intratumoral CD8+T cell activity. Neither TCR nor BCR diversity was independent prognostic biomarkers of survival across multiple cancer types. However, both TCR and BCR diversity improved the performance of predictive models combined with established biomarkers of response to immunotherapy.Conclusion Overall, these data indicate a currently unexplored immunological role of intratumoral B-cells associated with BCR diversity and antibody responses but independent of classical anticancer T-cells intratumoral activities.

Background: Although the expression of tight junction protein claudins (CLDNs) is well known in common histological subtypes of lung cancer, it has not been investigated in rare lung cancers. The aim of our study was to examine the expression of different CLDNs in pulmonary salivary gland tumors.Methods: 35 rare lung cancers including pathologically confirmed 12 adenoid cystic carcinomas (ACCs) and 23 mucoepidermoid carcinomas (MECs) were collected retrospectively. Immunohistochemical (IHC) staining was performed on formalin fixed paraffin embedded (FFPE) tumor tissues, and CLDN1, -2, -3, -4, -5, -7, and -18 protein expressions were analyzed. The levels of immunopositivity were determined with H-score. Certain pathological characteristics of ACC and MEC samples (tumor grade, presence of necrosis, presence of blood vessel infiltration, and degree of lymphoid infiltration) were also analyzed.Results: CLDN overexpression was observed in both tumor types, especially in CLDN2, -7, and -18 IHC. Markedly different patterns of CLDN expression were found for ACC and MEC tumors, especially for CLDN1, -2, -4, and -7, although none of these trends remained significant after correction for multiple testing. Positive correlations between expressions of CLDN2 and -5, CLDN3 and -4, and CLDN5 and -18 were also demonstrated. Tumors of never-smokers presented lower levels of CLDN18 than tumors of current smokers (p-value: 0.003).Conclusion: This is the first study to comprehensively describe the expression of different CLDNs in lung ACC and MEC. Overexpression of certain CLDNs may pave the way for targeted anti-claudin therapy in these rare histological subtypes of lung cancer.

Abstract PARP inhibitors were recently approved for treatment of molecularly-defined subsets of metastatic castrate-resistant prostate cancer (mCRPC) patients. Although the PARP inhibitor olaparib was approved for use in patients with a mutation in one of fourteen genes, the mutation frequency of the genes varies widely in mCRPC and the impact of the less commonly altered genes on PARP inhibitor sensitivity is uncertain. We used functional approaches to directly test the impact of PALB2 and BARD1 loss on homologous recombination (HR) function and PARP inhibitor sensitivity in prostate cancer cell lines. PALB2 or BARD1 loss led to decreased HR function as measured by loss of radiation-induced Rad51 foci formation as well as decreased HR capacity in a cell-based reporter assay. PALB2 or BARD1 loss also significantly increased sensitivity to the PARP inhibitors olaparib and rucaparib across a panel of prostate cancer cell lines. These data support PALB2 and BARD1 loss as markers of clinically relevant PARP inhibitor sensitivity and highlight the potential to use functional approaches to complement and extend findings from clinical trials of targeted agents.

Background: Our knowledge is still limited about the characteristics and treatment of rare lung tumors. The aim of our study was to determine programmed cell death ligand-1 (PD-L1) and programmed cell death-1 (PD-1) expression in rare pulmonary tumors to assess the potential role of immunotherapy.Methods: 66 pathologically confirmed rare lung tumors including 26 mucoepidermoid carcinomas (MECs), 27 adenoid cystic carcinomas (ACCs), and 13 tracheobronchial papillomas (TBPs) were collected retrospectively. Immunohistochemical (IHC) staining was performed on formalin fixed paraffin embedded (FFPE) tumor tissues, and PD-L1 expression on tumor cells (TCs) and immune cells (ICs), and PD-1 expression on ICs were determined. The cut off value for positive immunostaining was set at 1% for all markers.Results: PD-L1 expression on TCs was observed in two cases of MEC (7.7%), one case of ACC (3.7%), and was absent in TBP samples. PD-L1 expression on ICs could be demonstrated in nine cases of MEC (34.6%), four cases of ACC (14.8%), and was absent in TBPs. All PD-L1 TC positive tumors were also PD-L1 IC positive. Higher expression level than 5% of PD-L1 TC and/or IC was observed only in one ACC and in two MEC patients. Among them, strong PD-L1 immunopositivity of >50% on TCs and of >10% on ICs could be demonstrated in one MEC sample. PD-L1 expression of ≥1% on ICs was significantly more common in MEC, than in TBP (p < 0.001). In MEC ≥1% PD-L1 TC or IC expressions were significantly more common in patients aged 55 or older, than in younger patients (p = 0.046, and p = 0.01, respectively). PD-1 expression on ICs was found in five cases of MEC (19.2%), four cases of ACC (14.8%), and in two cases of TBP (15.4%). Only one MEC case showed a higher than 5% expression level of PD-1 on ICs.Conclusion: This retrospective study comprehensively demonstrated the rare expression of PD-L1 and PD-1 in pulmonary MEC, ACC, and TBP. However, we found very strong PD-L1 immunopositivity on both TCs and ICs in one MEC sample, which warrants further investigations in a larger cohort.

Loss of BRCA1 or BRCA2 results in genomic instability; however most studies have focused on the role of these proteins in double-strand break repair. Here the authors coupled cell line genetics and whole genome sequencing to investigate the formation of base substitutions and short indels in BRCA1-deficient cells, revealing a role for translesion DNA synthesis regulated by 53BP1.

Abstract Background The diversity of genomic alterations in cancer poses challenges to fully understanding the etiologies of the disease. Recent interest in infrequent mutations, in genes that reside in the “long tail” of the mutational distribution, uncovered new genes with significant implications in cancer development. The study of cancer-relevant genes often requires integrative approaches pooling together multiple types of biological data. Network propagation methods demonstrate high efficacy in achieving this integration. Yet, the majority of these methods focus their assessment on detecting known cancer genes or identifying altered subnetworks. In this paper, we introduce a network propagation approach that entirely focuses on prioritizing long tail genes with potential functional impact on cancer development. Results We identify sets of often overlooked, rarely to moderately mutated genes whose biological interactions significantly propel their mutation-frequency-based rank upwards during propagation in 17 cancer types. We call these sets “upward mobility genes” and hypothesize that their significant rank improvement indicates functional importance. We report new cancer-pathway associations based on upward mobility genes that are not previously identified using driver genes alone, validate their role in cancer cell survival in vitro using extensive genome-wide RNAi and CRISPR data repositories, and further conduct in vitro functional screenings resulting in the validation of 18 previously unreported genes. Conclusion Our analysis extends the spectrum of cancer-relevant genes and identifies novel potential therapeutic targets.

The anticancer immune response is shaped by immunogenic cell stress and death pathways. Thus, cancer cells can release danger-associated molecular patterns that act on pattern recognition receptors expressed by dendritic cells and their precursors to elicit an antitumor immune response. Here, we investigated the impact of single nucleotide polymorphisms (SNPs) in genes affecting this cancer-immunity dialogue in the context of head and neck squamous cell carcinoma (HNSCC). We observed that homozygosity for a loss-of-function SNP (rs2241880, leading to the substitution of a threonine residue in position 300 by an alanine) affecting autophagy related 16 like 1 (ATG16L1) is coupled to poor progression-free survival in platinum-treated HNSCC patients. This result was obtained on a cohort of patients enrolled at the Gustave Roussy Cancer Campus and was validated on an independent cohort of The Cancer Genome Atlas (TCGA). Homozygosity in rs2241880 is well known to predispose to Crohn’s disease, and epidemiological associations between Crohn’s disease and HNSCC have been reported at the levels of cancer incidence and prognosis. We speculate that rs2241880 might be partially responsible for this association.

Immune checkpoint inhibitor therapy has dramatically improved survival in a significant subset of patients with several solid tumor types. Increasing the number of patients benefitting from this form of therapy is an important translational research goal. Correlations between the composition of the gut microbiome and response to immune checkpoint inhibitor therapy raised the possibility that direct modulation of the gut microbiome may significantly improve the clinical benefit of this treatment. Several lines of observations suggest that tumor-associated carbohydrates, including those recognized as blood group-related glycolipid antigens, such as the Forssman antigen, may be some of the key factors behind this clinical correlation. Such antigens are expressed in human cancer, humans often produce antibodies against those, and they can induce antibody directed cellular cytotoxicity. Importantly, these antibodies are often induced by antigens present in microbes of the gut. If identified, these antibodies could be boosted by appropriate vaccination techniques and thus enhance anti-tumor immunity with minimal side effects. [ABSTRACT FROM AUTHOR]

Background: Metastatic urothelial carcinoma (mUC) has a poor prognosis, despite recent therapeutic advancements. Prostaglandin Reductase 1 (PTGR1) is essential for activating acylfulvens, a promising class of drugs for treating a subset of urothelial carcinoma (UC) patients. The efficacy of acylfulvens depends on PTGR1 activity and defects in the nucleotide excision repair (NER) pathway, notably ERCC2 mutations present in 10–15% of bladder tumors. This study identifies patients eligible to be included in acylfulven clinical trials based on the presence of PTGR-1 by immunohistochemistry (IHC) staining, RNA expression level and mutations in the NER pathway. Additionally, it evaluates PTGR-1 expression as a prognostic biomarker. Methods: Three PTGR-1 antibodies were tested in a kidney cancer cell line A498 and in tissues with known PTGR1 expression (liver, tonsils, pancreas, small intestine, etc.). Patients with untreated mUC receiving 1st line platinum from Dec. 2019 to Dec. 2021 in the Capital Region, Denmark, were included retrospectively. FFPE tumor samples were collected, and tissue microarrays (TMAs) were constructed. TMAs were stained with the best-performing PTGR1 antibody, RNA expression was analyzed using Nanostring nCounter PanCancer panel and gene mutations were assessed using a targeted genomic panel (TSO-500). Kaplan-Meier and multivariate Cox regression assessed overall survival and covariate impacts. Results: The AB181131 PTGR1 antibody was the most reliable in validation tissues. Tumors from 71 mUC patients were used to construct the TMA, and 40% of tumors scored positive for PTGR1 by IHC staining. A normalized PTGR1 RNA cutoff at 2,550 normalized counts achieved an AUC of 0.9, defining 35 samples as positive with a sensitivity of 96% and specificity of 85% in relation to IHC-positivity. Differential expression showed a significant upregulation of PTGR1 RNA in PTGR1 IHC-positive cases. NER-deficiency and PTGR1 positivity (mutations in ERCC1, ERCC2, ERCC3, ERCC4) was seen in 9 patients (13%). Median overall survival was 16 months in the cohort. Overall survival (OS) analysis indicates that overexpression of PTGR1 RNA was associated with a reduced median OS (12 months vs. 25 months, p = 0.039, log-rank). Conclusion: PTGR1 IHC staining pattern using the Abcam AB181131 antibody is highly correlated with PTGR1 RNA expression. 13% in our cohort were identified as NER deficient and PTGR1 positive. Lower levels of PTGR1 indicates better outcome in this cohort. [ABSTRACT FROM AUTHOR]

Abstract PARP inhibitors are approved for the treatment of solid tumor types that frequently harbor alterations in the key homologous recombination (HR) genes, BRCA1/2. Other tumor types, such as lung cancer, may also be HR deficient, but the frequency of such cases is less well characterized. Specific DNA aberration profiles (mutational signatures) are induced by homologous recombination deficiency (HRD) and their presence can be used to assess the presence or absence of HR deficiency in a given tumor biopsy even in the absence of an observed alteration of an HR gene. We derived various HRD-associated mutational signatures from whole-genome and whole-exome sequencing data in the lung adenocarcinoma and lung squamous carcinoma cases from TCGA, and in a patient of ours with stage IVA lung cancer with exceptionally good response to platinum-based therapy, and in lung cancer cell lines. We found that a subset of the investigated cases, both with and without biallelic loss of BRCA1 or BRCA2, showed robust signs of HR deficiency. The extreme platinum responder case also showed a robust HRD-associated genomic mutational profile. HRD-associated mutational signatures were also associated with PARP inhibitor sensitivity in lung cancer cell lines. Consequently, lung cancer cases with HRD, as identified by diagnostic mutational signatures, may benefit from PARP inhibitor therapy.

Human endogenous retroviruses (HERV) normally remain quiescent, but can be reactivated by malignant transformation. Here the authors find, via HERV peptide library testing and tetramer validation, more profound HERV transcription and associated T cell recognition in myeloid cancer patients to implicate HERVs as potential therapeutic targets.

Background Metastatic lung cancer is a debilitating disease, but with the advances in immunotherapy, therapeutic options have vastly increased. Numerous complete blood count parameters (CBC) have been described as easily accessible biomarkers that might predict response to immunotherapy. However, to date, no comprehensive study has been performed on the longitudinal changes of these parameters during cancer progression. Methods The clinicopathological variables and CBC parameters of 986 advanced stage lung cancer patients were retrospectively analyzed. Blood tests were performed as part of the routine checkup and the results were recorded at the time of the diagnosis of the primary tumor, the diagnosis of brain or bone metastases, and also during the last available follow‐up. Results In the experimental subcohort, 352 and 466 patients were diagnosed with brain and bone metastases, respectively. The control group consisted of 168 patients without clinically detectable or other distant organ metastases. In our longitudinal analyses, we found significantly decreasing absolute lymphocyte count (ALC: P

Both sensory neurons and immune cells, albeit at markedly different levels, express the vanilloid (capsaicin) receptor, Transient Receptor Potential, Vanilloid-1 (TRPV1). Activation of TRPV1 channels in sensory afferent nerve fibers induces local effector functions by releasing neuropeptides (most notably, substance P) which, in turn, trigger neurogenic inflammation. There is good evidence that chronic activation or inactivation of this inflammatory pathway can modify tumor growth and metastasis. TRPV1 expression was also demonstrated in a variety of mammalian immune cells, including lymphocytes, dendritic cells, macrophages and neutrophils. Therefore, the effects of TRPV1 agonists and antagonists may vary depending on the prominent cell type(s) activated and/or inhibited. Therefore, a comprehensive understanding of TRPV1 activity on immune cells and nerve endings in distinct locations is necessary to predict the outcome of therapies targeting TRPV1 channels. Here, we review the neuro-immune modulation of cancer growth and metastasis, with focus on the consequences of TRPV1 activation in nerve fibers and immune cells. Lastly, the potential use of TRPV1 modulators in cancer therapy is discussed.

BACKGROUND Neoantigen-driven recognition and T cell–mediated killing contribute to tumor clearance following adoptive cell therapy (ACT) with tumor-infiltrating lymphocytes (TILs). Yet how diversity, frequency, and persistence of expanded neoepitope-specific CD8+ T cells derived from TIL infusion products affect patient outcome is not fully determined.METHODS Using barcoded pMHC multimers, we provide a comprehensive mapping of CD8+ T cells recognizing neoepitopes in TIL infusion products and blood samples from 26 metastatic melanoma patients who received ACT.RESULTS We identified 106 neoepitopes within TIL infusion products corresponding to 1.8% of all predicted neoepitopes. We observed neoepitope-specific recognition to be virtually devoid in TIL infusion products given to patients with progressive disease outcome. Moreover, we found that the frequency of neoepitope-specific CD8+ T cells in TIL infusion products correlated with increased survival and that neoepitope-specific CD8+ T cells shared with the infusion product in posttreatment blood samples were unique to responders of TIL-ACT. Finally, we found that a transcriptional signature for lymphocyte activity within the tumor microenvironment was associated with a higher frequency of neoepitope-specific CD8+ T cells in the infusion product.CONCLUSIONS These data support previous case studies of neoepitope-specific CD8+ T cells in melanoma and indicate that successful TIL-ACT is associated with an expansion of neoepitope-specific CD8+ T cells.FUNDING NEYE Foundation; European Research Council; Lundbeck Foundation Fellowship; Carlsberg Foundation.

Detecting the entire repertoire of tumor-specific reactive tumor-infiltrating lymphocytes (TILs) is essential for investigating their immunological functions in the tumor microenvironment. Current in vitro assays identifying tumor-specific functional activation measure the upregulation of surface molecules, de novo production of antitumor cytokines, or mobilization of cytotoxic granules following recognition of tumor-antigens, yet there is no widely adopted standard method. Here we established an enhanced, yet simple, method for identifying simultaneously CD8+ and CD4+ tumor-specific reactive TILs in vitro, using a combination of widely known and available flow cytometry assays. By combining the detection of intracellular CD137 and de novo production of TNF and IFNγ after recognition of naturally-presented tumor antigens, we demonstrate that a larger fraction of tumor-specific and reactive CD8+ TILs can be detected in vitro compared to commonly used assays. This assay revealed multiple polyfunctionality-based clusters of both CD4+ and CD8+ tumor-specific reactive TILs. In situ, the combined detection of TNFRSF9, TNF, and IFNG identified most of the tumor-specific reactive TIL repertoire. In conclusion, we describe a straightforward method for efficient identification of the tumor-specific reactive TIL repertoire in vitro, which can be rapidly adopted in most cancer immunology laboratories.