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DNA mismatch repair complex is involved in the maintenance of DNA stability. In the recent years, a plethora of technical approaches for microsatellite instability (MSI) analysis emerged. Here, we review the results of our MSI status evaluation by adopting a customised workflow on microfluidic system obtained in 4 years of diagnostic routine practice. Data from MSI status were retrieved from our institutional archive covering the period from January 2017 to December 2021. Microfluidic analysis was carried out on microfluidic platform. Results were inspected with a proprietary software. Overall, microsatellite stability (MSS) and MSI-high (MSI-H) profile was detected in n=423/458 (92.36%) and n=35/458 (7.64%) patients with metastatic CRC (mCRC), respectively. In addition, n=78/86 (90.70%) and n=8/86 (9.30%) patients without CRC showed an MSS and MSI-H profile. This review highlights the suitability of microfluidic approach in patients with cancer for MSI testing.

AimsGene fusions assays are key for personalised treatments of advanced human cancers. Their implementation on cytological material requires a preliminary validation that may make use of cell line slides mimicking cytological samples. In this international multi-institutional study, gene fusion reference standards were developed and validated.MethodsCell lines harbouring EML4(13)–ALK(20) and SLC34A2(4)–ROS1(32) gene fusions were adopted to prepare reference standards. Eight laboratories (five adopting amplicon-based and three hybridisation-based platforms) received, at different dilution points two sets of slides (slide A 50.0%, slide B 25.0%, slide C 12.5% and slide D wild type) stained by Papanicolaou (Pap) and May Grunwald Giemsa (MGG). Analysis was carried out on a total of 64 slides.ResultsFour (50.0%) out of eight laboratories reported results on all slides and dilution points. While 12 (37.5%) out of 32 MGG slides were inadequate, 27 (84.4%) out of 32 Pap slides produced libraries adequate for variant calling. The laboratories using hybridisation-based platforms showed the highest rate of inadequate results (13/24 slides, 54.2%). Conversely, only 10.0% (4/40 slides) of inadequate results were reported by laboratories adopting amplicon-based platforms.ConclusionsReference standards in cytological format yield better results when Pap staining and processed by amplicon-based assays. Further investigation is required to optimise these standards for MGG stained cells and for hybridisation-based approaches.

AimsIn thyroid cytopathology, the undetermined diagnostic categories still pose diagnostic challenges. Although next-generation sequencing (NGS) is a promising technique for the molecular testing of thyroid fine-needle aspiration (FNA) specimens, access to such technology can be difficult because of its prohibitive cost and lack of reimbursement in countries with universal health coverage. To overcome these issues, we developed and validated a novel custom NGS panel, Nexthyro,specifically designed to target 264 clinically relevant mutations involved in thyroid tumourigenesis. Moreover, in this study, we compared its analytical performance with that of our previous molecular testing strategy.MethodsThe panel, which includes 15 genes (BRAF, EIF1AX, GNAS, HRAS, IDH1, KRAS, NF2, NRAS, PIK3CA, PPM1D, PTEN, RET, DICER1, CHEK2, TERT promoter),was validated with a cell-line derived reference standard and 72 FNA archival samples previously tested with the 7-gene test.ResultsNexthyroyielded 100% specificity and detected mutant alleles at levels as low as 2%. Moreover, in 5/72 (7%) FNAs, it detected more clinically relevant mutations in BRAFand RASgenes compared with the 7-gene test. Nexthyroalso revealed better postsequencing metrics than the previously adopted commercial ‘generic’ NGS panel.ConclusionOur comparative analysis indicates that Nexthyrois a reliable NGS panel. The study also implies that a custom-based solution for routine thyroid FNA is sustainable at the local level, allowing patients with undetermined thyroid nodules affordable access to NGS.

Purpose: The efficacy of lenvatinib for advanced and progressive radioactive iodine refractory differentiated thyroid cancer is well established. Herein, we retrospectively evaluated the long-term safety and efficacy of lenvatinib in 23 patients treated at a single Institution. Methods: Clinical data of all patients treated for a differentiated thyroid cancer with lenvatinib from April 2015 to September 2020 were retrospectively analyzed. Results: A total of 23 patients were included. In all, 21 patients received lenvatinib as first-line systemic therapy. Median age at initiation of lenvatinib treatment was 68 (44–90) years. Median duration of the study from initiation of lenvatinib to study end was 23 (2–65) months. The indication for lenvatinib treatment was documented progression of distant metastases in 20 patients and of locally advanced disease in the other 3 and median duration of lenvatinib therapy was 15 (2–64) months. Best treatment responses were: partial response in 6 patients, stable disease in 14, progressive disease in 1, and not evaluable in 2. Median progression-free survival was 25 months (95% CI: 12–40) and median overall survival was 46 months (95% CI: 28–65). Three patients had to discontinue lenvatinib treatment due to serious adverse events and no drug-related death was observed. Ten patients continued lenvatinib for more than 24 months and the only newly registered adverse event after this period of time was one case of G2 proteinuria. Six patients continued lenvatinib treatment beyond documented tumor progression due to oligoprogression or slowly progressive disease (median time 18.5 months, 8–42 months). A total of 14 patients were alive at the end of the study: 11 showed partial response/stable disease on lenvatinib, including 3 who had a stable disease after local ablative therapy for oligoprogressive metastases; 3 had to change treatment, including 2 for lenvatinib-related serious adverse events and 1 for progressive disease. Conclusions: Long-term lenvatinib treatment is safe and some patients may experience persistent long-term control of the disease. Late treatment-related AEs rarely occurred. Oligoprogressive and slowly progressive disease can be managed without treatment withdrawal as long as there are some clinical benefits.

AimsIn the time of COVID-19, predictive molecular pathology laboratories must still timely select oncological patients for targeted treatments. However, the need to respect social distancing measures may delay results generated by laboratory-developed tests based on sequential steps a long hands-on time. Laboratory workflows should now be simplified.MethodsThe organisation of the University of Naples Federico II predictive pathology laboratory was assessed before (March–April 2019) and during (March–April 2020) the Italian lockdown.ResultsThe number of patients undergoing single or multiple biomarker testing was similar in 2019 (n=43) and in 2020 (n=45). Considering adequate samples for molecular testing, before the outbreak, next-generation sequencing was mostly used (35/42, 83.3%). Testing six genes had a reagent cost of €98/patient. Conversely, in 2020, almost all cases (38/41, 92.7%) were analysed by automated testing. This latter had for any single assay/gene a significant reagent cost (€95–€136) and a faster mean turnaround time (5.3 vs 7.9 working days).ConclusionIn the times of coronavirus, laboratory fully automated platforms simplify predictive molecular testing. Laboratory staff may be more safely and cost-effectively managed.

AimsLung cancer predictive biomarker testing is essential to select advanced-stage patients for targeted treatments and should be carried out without delays even during health emergencies, such as the coronavirus (COVID-19) outbreak.MethodsFifteen molecular laboratories from seven different European countries compared 4 weeks of national lockdown to a corresponding period in 2019, in terms of tissue and/or plasma-based molecular test workload, analytical platforms adopted, number of cases undergoing programmed death-ligand1 (PD-L1) expression assessment and DNA-based molecular tests turnaround time.ResultsIn most laboratories (80.0%), tissue-based molecular test workload was reduced. In 40.0% of laboratories (6/15), the decrease was >25%, and in one, reduction was as high as 80.0%. In this instance, a concomitant increase in liquid biopsy was reported (60.0%). Remarkably, in 33.3% of the laboratories, real-time PCR (RT-PCR)-based methodologies increased, whereas highly multiplexing assays approaches decreased. Most laboratories (88.9%) did not report significant variations in PD-L1 volume testing.ConclusionsThe workload of molecular testing for patients with advanced-stage lung cancer during the lockdown showed little variations. Local strategies to overcome health emergency-related issues included the preference for RT-PCR tissue-based testing methodologies and, occasionally, for liquid biopsy.

Purpose: Nowadays, the clinical management of thyroid nodules needs to be multi-disciplinary. In particular, the crosstalk between endocrinologists and cytopathologists is key. When FNAs are properly requested by endocrinologists for nodules characterised by relevant clinical and ultrasound features, cytopathologists play a pivotal role in the diagnostic work-up. Conversely, improper FNA requests can lead to questionable diagnostic efficiency. Recently, recommendations to delay all non-urgent diagnostic procedures, such as thyroid FNAs, to contain the spread of COVID-19 infection, have made the interplay between endocrinologists and cytopathologists even more essential. The objective of this study was to assess the impact of COVID-19 pandemic on our practice by evaluating the total number of FNAs performed and the distribution of the Bethesda Categories before, during, and after the lockdown. Methods: We analysed the FNA trends before (1st January 2019 to March 13th 2020), during (March 14th to May 15th), and after (May 16th to July 7th) the lockdown. Results: Although the total number of weekly FNAs dropped from 62.1 to 23.1, our referring endocrinologists managed to prioritise patients with high-risk nodules. In fact, in the post-lockdown, the weekly proportion of benign diagnoses dropped on average by 12% and that of high-risk diagnoses increased by 6%. Conclusions: The lesson we have learned so far from this pandemic is that by applying safety protocols to avoid contagion and by increasing the threshold for FNA requests for thyroid nodules, we can continue to guarantee our services to high-risk patients even in times of a health crisis.

AimsOur laboratory is a centralised centre receiving routine non-small cell lung cancer (NSCLC) samples for programmed death ligand-1 (PD-L1) immunohistochemical (IHC) evaluation. Since literature data are not concordant here we review our clinical records to assess the rate of PD-L1 positive and negative NSCLC cases in real-world practice.MethodsPD-L1 expression was evaluated by a validated 22C3 IHC laboratory developed test on 211 prospectively collected routine NSCLC samples, received from 10 outside institutions. PD-L1 expression was assessed by the tumour proportion score (TPS) and reported by using a three cut-point system: TPS<1, TPS 1%–49% and TPS≥50%.ResultsOverall, 193 out of 211 samples (91.5%) meet the criteria for adequacy (more than 100 viable neoplastic cells). In 62.7% (121/193) of samples TPS was <1%; 17.6% of samples (34/193) expressed PD-L1 with a TPS of 1%–49% and 19.7% (38/193) with a TPS of >50%. There was no significant difference in PD-L1 expression rates between different histotypes and site of sampling. Instead, a statistically significant difference was associated to the type of samples: in fact, cytological samples were more frequently negative for PD-L1 expression (TPS<1%) and less often displayed PD-L1 expression at high levels (TPS>50%) than surgical resections and biopsies.ConclusionsWe present a referral laboratory experience on IHC PD-L1 expression of prospectively collected routine NSCLC samples. Data from the real-world practice can better clarify the percentage of PD-L1 positive and negative cases, to establish benchmarks for good practice standards.

AimThe rapid and fully automated Idylla EGFRMutation Assay has been specifically designed to process formalin-fixed, paraffin-embedded sections without requiring preliminary DNA extraction. This study evaluates whether this approach can also process archival smears from patients with non–small cell lung cancer (NSCLC) by scraping the stained cellular material directly into the cartridge.MethodsThe study was divided into two parts. In the first part, we carried out Idylla EGFRMutation Assay on archival stained smears from 39 patients with NSCLC. Among these, 14 cases harboured a mutation in either exon 19 (n=11) or exon 21 (n=3), previously detected on DNA extracts by fragment length and TaqMan assays. In the second part, we evaluated whether de-staining of the smears could reduce background fluorescence.ResultsThe Idylla EGFRMutation Assay confirmed the presence of EGFRmutation in 11 instances (78.6%). However, concordance was higher for exon 19 deletions (10/11) than for exon 21 p.L858R assessments. Raw data showed a high background fluorescence in channel 2, where the EGFRexon 21 p.L858R mutation was detected. This interference, due to dye residues from the original staining, was partially reduced by de-staining the cytological material.ConclusionsOur data, although preliminary, show that the Idylla EGFRMutation Assay can reliably process most archival smears without requiring preliminary DNA extraction. Results may be further improved by de-staining the cellular material before insertion into the cartridge.

AimsFollowing the development for liquid biopsies of the SiRe next-generation sequencing (NGS) panel that covers 568 clinical relevant mutations in EGFR, KRAS, NRAS, BRAF, cKITand PDGFRagenes, in this current study, we apply this small NGS panel on tissue samples of lung cancer.MethodsA total of 322 specimens were prospectively tested. Technical parameters were analysed on both cytological and histological samples. In a subset of 75 samples, the EGFRSiRe results were compared with those generated by the European Community (CE)–IVD EGFRassay on Idylla platform. Clinical outcomes of 11 patients treated, on the basis of SiRe results, were also evaluated.ResultsOnly 28 (8.7%) specimens failed to produce a library; out of the 294 remaining samples, a total of 168 somatic mutations were found. In nearly all instances (74/75–99%), the EGFRSiRe results were confirmed by Idylla. In general, SiRe analytical parameters were excellent. However, histological and cytological specimens differed in relation to average reads for sample, mean number of mapped reads, median read length and average reads for amplicon. Treatment outcome evaluation in 11 patients showed a partial response in 82 % (9/11) patients with a median progression-free survival of 340 days.ConclusionsThe small gene panel SiRe is a clinically relevant tool useful to widespread the adoption of NGS in predictive molecular pathology laboratories.

IntroductionThe coronavirus disease 2019 (COVID-19) is changing the way we practice pathology, including fine needle aspiration (FNA) diagnostics. Although recommendations have been issued to prioritise patients at high oncological risk, postponing those with unsuspicious presentations, real world data have not been reported yet.MethodsThe percentages of the cytological sample types processed at the University of Naples Federico II, during the first 3 weeks of Italian national lockdown were compared with those of the same period in 2019.ResultsDuring the emergency, the percentage of cytology samples reported as malignant increased (p<0.001), reflecting higher percentages of breast (p=0.002) and lymph nodes FNAs (p=0.008), effusions (p<0.001) and urine (p=0.005). Conversely, thyroid FNAs (p<0.001) and Pap smears (p=0.003) were reduced.ConclusionsEven in times of COVID-19 outbreak, cytological examination may be safely carried out in patients at high oncological risk, without the need to be postponed.

Background Analysis of K- and N-RAS mutations is mandatory before planning treatment of metastatic colorectal cancer, because only RAS wild-type (WT) patients can benefit from treatment with anti-EGFR monoclonal antibodies (cetuximab and panitumumab).Case report Here we report the case of a 69-year-old male patient affected by metastatic sigmoid cancer. He underwent left hemicolectomy, and histology diagnosed a well-differentiated, pT4, node-positive adenocarcinoma; KRAS analysis performed with direct sequencing identified a mutation in exon 2 of the KRAS gene (GGT->GTT). After first-line chemotherapy with FOLFOX6 plus bevacizumab, the patient underwent surgical resection of residual liver metastases. Histology showed metastatic deposits from colic adenocarcinoma with extensive coagulative necrosis. Mutational analysis of the KRAS gene was also performed on liver metastases by pyrosequencing assay, and no mutation was identified. Due to the discordant results (GGT->GTT exon 2 KRAS mutation in the primary tumor, and KRAS-WT in the liver metastases), mutational analysis on liver metastasis was repeated using next-generation sequencing and enriching the sample in tumor cells by manual microdissection; the same type of mutation of the primary tumor (GGT->GTT exon 2 KRAS gene) was confirmed.Conclusions Accurate tissue sampling and adequately sensitive assays are essential to correctly identify colorectal cancer patients who can be treated with an anti-EGFR monoclonal antibody.

In the advanced stages of non-small cell lung cancer (NSCLC), molecular testing is often performed on archival cytological smears. The nCounter system (NanoString Technologies) is a new promising multiplex digital colour-coded barcode technology. However, its feasibility to evaluate the RNA expression of clinical relevant biomarkers on routine cytological smears is still uncertain. To this end, RNA was extracted from 12 NSCLC routine stained cytological smears, and nCounter analysis performed by using a 48-gene panel. Overall, 11/12 (92%) of the smears were adequate for the secondary analysis, fulfilling the quality check parameter analysis of nSolver software. This pilot study shows that RNA nCounter analysis is feasible on routine cytological smears preparing the field for the implementation of this technology in the routine setting.

Non-small cell lung carcinoma harbouring epidermal growth factor receptor (EGFR) mutation, usually progress after an initial response to tyrosine-kinase inhibitors (TKI). Liquid biopsy enables with a simple blood draw the accurate detection of EGFRp.T790M mutation, the most common resistance mechanism, avoiding the more invasive tissue re-biopsy. However, in a subset of cases, resistance mechanisms are more complex featuring both genetic and morphological changes. Here we report the case of a 67 years-old woman, affected by an EGFRmutated lung adenocarcinoma and treated by TKI. At disease progression, the patient developed a morphological transition to squamous cell carcinoma in association to the arising of a PIK3CAp.E542K mutant subclone. This case illustrates that, even in the “liquid biopsy” era, cytology can have still a role by providing an overall assessment of both morphology and genetic TKI resistance mechanisms.

This review is focused on the challenges in standardising and optimising molecular testing workflow in cytopathology. Although cytological samples yield optimal quality DNA, whose minimal amounts in most cases suffice even for multigene mutational profiling, the success of molecular testing is strongly dependent on standardised preanalytical protocols for maximising DNA yield and quality. Sample cytopreparation influences, even more, the quality of RNA and consequently the potential success of reverse transcription-PCR. Here, the educational and technical involvement of the cytopathologist as a relevant component of a multidisciplinary team, in the issues related to test request, specimen collection, fixation, processing, staining, tumour fraction enrichment, DNA quality/quantity assessment and storage conditions is discussed. In addition, the specific sample requirements related to more recent technological developments are examined, underlining the modern role of the cytopathologist, whose continuous education is crucial to meet the opportunities of molecular medicine.

AimsIn everyday practice, epidermal growth factor receptor (EGFR) testing is centralised in referral laboratories that receive paucicellular cytological specimens. Ideally, EGFRtesting should be carried out in the centre where the patient is diagnosed such that the most cellular slide can be selected from in-house collected cytological material. However, available techniques are little standardised and difficult to be implemented in settings with little expertise in molecular testing. The Idylla EGFRprototype assay is a rapid and fully automated test which may easily be adopted by a wider number of pathological centres. This study assessed whether an Idylla EGFRprototype assay can be reliably applied to cytological lung cancer specimens.MethodsThe limit of detection (LOD) of the Idylla EGFRprototype assay was assessed by cell line dilution studies. A total of 10 ng was directly placed inside an Idylla EGFRprototype assay cartridge. Idylla results were compared with fragment length (exon 19 del) and Taqman assays.ResultsThe Idylla EGFRprototype assay showed an LOD of 1% mutant allele and yielded valid results in 74/76 (97.3%) samples, detecting all the mutant cases (n=32) identified by standard techniques; in addition, Idylla detected two low abundance EGFRexon 19 deletions and two G719X exon 18 point mutations, not covered by our standard reference method.ConclusionsIdylla EGFRprototype assay is sensitive on extracted DNA and can reliably be applied on cytological samples, enabling implementation of EGFRtesting even in less experienced diagnostic units.

Spindle epithelial tumor with thymus-like differentiation (SETTLE) is a very rare tumor of the thyroid gland. An algorithm for the diagnosis and treatment of SETTLE has yet to be established. The aim of this study was to identify all case reports of SETTLE and to compare the clinical-pathological features and therapy of the cases identified. We performed a PubMed search for case reports of SETTLE in English published up to November 2014 in which “SETTLE” and “Spindle epithelial tumor with thymus-like differentiation” were keywords. We identified 35 articles for a total of 42 cases. We found that SETTLE usually occurs in children and adolescents as an asymptomatic neck mass. Thyroid function tests and tumor markers are invariably within normal range in all patients, and fine needle aspiration biopsy is rarely diagnostic for SETTLE. All 42 patients had undergone thyroidectomy. After surgical resection, chemotherapy (adjuvant or first/second-line treatment) and/or radiotherapy were administered to control tumor growth in cases with metastatic involvement. Although SETTLE presents a low-grade malignancy, it can metastasize to lymph nodes, the mediastinum, lung, vertebrae, and kidney even many years after the initial diagnosis. SETTLE may have a good prognosis if appropriately treated at initial presentation and if patients undergo long-term monitoring with regular clinical and morphological evaluations.

SUMMARY Developments in predictive molecular testing and personalized therapy of lung cancer have recently called for a major change in the histological and cytological activity requiring the pathologist to strictly connect with pulmonologists, oncologists and molecular biologists to improve patient management. Different clinical trials established that tyrosine kinase inhibitor therapy is superior to chemotherapy, when patients harbor EGFRmutations. Similarly, the patients whose lung carcinoma carries ALKfusion genes consistently respond to ALK inhibitors. These improvements have led to the understanding that the morphological diagnosis of lung adenocarcinoma requires a multidisciplinary approach; even more recently the College of American Pathologists, the International Association for the Study of Lung Cancer and the Association for Molecular Pathology encouraged to develop international guidelines for lung cancer biomarker testing. This paper summarizes the practical impact of these guidelines, focusing on the pathologist's role in daily EGFRtesting practice.

Both experimental and clinical studies have suggested that any potential treatment of polycystic kidney disease (PKD) should start early and last for a long time to be effective, with unavoidable side reactions and considerable costs. The aim of the present study was to test how low doses of rapamycin (RAPA; 0.15 mg/kg ip for 4 days/wk), tolvaptan (TOLV; 0.005% in diet), or AEZ-131 (AEZ; a novel ERK inhibitor, 30 mg/kg for 3 days/wk by gavage), alone and in association, affect the progression of polycystic renal disease in PCK rats. Rats were treated for 8 wk starting at 4–6 wk of age. The efficacy of low doses of such drugs in inhibiting their respective targets was confirmed by immunoblot experiments. Compared with rats in the control (CON) group, RAPA treatment caused a significant reduction in cyst volume density (CVD; −19% vs. the CON group) and was numerically similar to that in TOLV-treated rats (−18%, not significiant), whereas AEZ treatment was not effective. RAPA + TOLV treatment resulted in a significantly lower CVD (−49% vs. the CON group) and was associated with a striking decrease in cAMP response element-binding protein phosphorylation, and similar data were detected in RAPA + AEZ-treated rats (−42%), whereas TOLV + AEZ treatment had virtually no effect. RAPA administration significantly lessened body weight gain, whereas TOLV administration resulted a mild increase in diuresis and a significant increase in cAMP urinary excretion. Histological data of tubular proliferation were in full agreement with CVD data. In conclusion, this study demonstrates that the association of low doses of RAPA, TOLV, and AEZ slows the progression of PKD with limited side effects, suggesting the use of combined therapies also in clinical trials.

In an increased number of settings, cytology represents the only source of sampling and it often substitutes histology as an independent diagnostic modality. Thus, DNA molecular targets to stratify patients for targeted therapy are often evaluated on cytology. In addition, DNA mutational tests may refine indeterminate thyroid and pancreas cytology. This review discusses the applications and limitations of DNA mutational testing on cytology. With respect to histology, most cytological samples have the advantages of a purer population of tumor cells, with low stromal component, a better preserved DNA, and assessing at the same time of sample collection cellular adequacy for DNA testing. However, since in vitro diagnostic tests are licensed only for paraffin-tissue, all mutational assays on cytology are “home brew,” requiring a rigorous validation process. This should take into account not only the performance characteristics of the molecular assay but also features inherent to any given cytological samples, such as its source, preparation type, fixation and staining modalities, and the most effective tumor cell enrichment methods. This calls for a change of cytotechnologists and cytopathologists mentality to collect and process the cytological samples not only for microscopy but also to assess clinically relevant molecular markers.

Although gene fusions occur rarely in non-small-cell lung cancer (NSCLC) patients, they represent a relevant target in treatment decision algorithms. To date, immunohistochemistry and fluorescence in situhybridization are the two principal methods used in clinical trials. However, using these methods in routine clinical practice is often impractical and time consuming because they can only analyze single genes and the quantity of tissue material is often insufficient. Thus, novel technologies, able to test multiple genes in a single run with minimal sample input, are being under investigation. Here, we discuss the utility of next-generation sequencing and nCounter technologies in detecting simultaneous gene fusions in NSCLC patients.