Current role of cytopathology in the molecular and computational era: The perspective of young pathologists.

Cytopathology represents a well established diagnostic approach because of its limited cost, reliability, and minimal invasiveness with respect to other methodologies. The evolving complexity of the different classifications systems and the implementation of ancillary techniques to refine the diagnosis is progressively helping in the risk of malignancy stratification, and the adoption of next-generation sequencing techniques contributes to enrich this valuable tool with predictive information, which is always more essential in the tailored medicine era. The recent introduction of digital and computational pathology is further boosting the potentialities of cytopathology, aiding in the interpretation of samples to improve the cost effectiveness of large screening programs and the diagnostic efficiency within intermediate/atypical categories. Moreover, the adoption of artificial intelligence tools is promising to complement molecular investigations, representing a stimulating perspective in the cytopathology field. In this work, the authors tried to summarize the multifaceted nature of this complex and evolving field of pathology, synthesizing the most recent advances and providing the young pathologists' perspective on this fascinating world.

A MiR181/Sirtuin1 regulatory circuit modulates drug response in biliary cancers.

Despite recent advances, biliary tract cancer (BTC) remains one of the most lethal tumor worldwide due to late diagnosis, limited therapeutic strategies and resistance to conventional therapies. In recent years, high-throughput technologies have enabled extensive genome, and transcriptome sequencing unveiling, among others, the regulatory potential of microRNAs (miRNAs). Compelling evidence shown that miRNA are attractive therapeutic targets and promising candidates as biomarkers for various therapy-resistant tumors. The analysis of miRNA profile successfully identified miR-181c and -181d as significantly downregulated in BTC patients. Low miR-181c and -181d expression levels were correlated with worse prognosis and poor treatment efficacy. In fact, progression-free survival analysis indicated poor survival rates in miR-181c and -181d low expressing patients. The expression profile of miR-181c and -181d in BTC cell lines revealed that both miRNAs were dysregulated. Functional in vitro experiments in BTC cell lines showed that overexpression of miR-181c and -181d affected cell viability and increased sensitivity to chemotherapy compared to controls. In addition, by using bioinformatic tools we showed that the miR-181c/d functional role is determined by binding to their target SIRT1 (Sirtuin 1). Moreover, BTC patients expressing high levels of miR-181 and low SIRT1 shown an improved survival and treatment response. An integrative network analysis demonstrated that, miR-181/SIRT1 circuit had a regulatory effect on several important metabolic tumor-related processes. Our study demonstrated that miR-181c and -181d act as tumor suppressor miRNA in BTC, suggesting the potential use as therapeutic strategy in resistant cancers and as predictive biomarker in the precision medicine of BTC.

BAP1 Loss, Nuclear Grading, and Nonepithelioid Features in the Diagnosis of Mesothelioma in Italy: Nevermore without the Pathology Report.

The pathologic diagnosis of pleural mesothelioma is generally based on international guidelines, but no compulsory points based on different drugs approvals in different European countries are required to be reported. According to the last (2021) edition of the World Health Organization classification of pleural tumors, the nuclear grade of epithelioid-type mesothelioma should be always inserted in the pathologic report, while the presence of BRCA-associated protein-1 (BAP1) (clone C4) loss and a statement on the presence of the sarcomatoid/nonepithelioid component are fundamental for both a screening of patients with suspected BAP1 tumor predisposition syndrome and the eligibility to perform first-line immunotherapy at least in some countries. Several Italian experts on pleural mesothelioma who are deeply involved in national scientific societies or dedicated working groups supported by patient associations agreed that the pathology report of mesothelioma of the pleura should always include the nuclear grade in the epithelioid histology, which is an overt statement on the presence of sarcomatoid components (at least 1%, in agreement with the last classification of pleural mesothelioma) and the presence of BAP1 loss (BAP1-deficient mesothelioma) or not (BAP1-retained mesothelioma) in order to screen patients possibly harboring BAP1 tumor predisposition syndrome. This review aims to summarize the most recent data on these three important elements to provide evidence regarding the possible precision needs for mesothelioma.

Economic assessment of NGS testing workflow for NSCLC in a healthcare setting.

Background: The molecular diagnostic and therapeutic pathway of Non-Small Cell Lung Cancer (NSCLC) stands as a successful example of precision medicine. The scarcity of material and the increasing number of biomarkers to be tested have prompted the routine application of next-generation-sequencing (NGS) techniques. Despite its undeniable advantages, NGS involves high costs that may impede its broad adoption in laboratories. This study aims to assess the detailed costs linked to the integration of NGS diagnostics in NSCLC to comprehend their financial impact. Materials and methods: The retrospective analysis encompasses 210 cases of early and advanced stages NSCLC, analyzed with NGS and collected at the IRCCS San Gerardo dei Tintori Foundation (Monza, Italy). Molecular analyses were conducted on FFPE samples, with an hotspot panel capable of detecting DNA and RNA variants in 50 clinically relevant genes. The economic analysis employed a full-cost approach, encompassing direct and indirect costs, overheads, VAT (Value Added Tax). Results: We estimate a comprehensive cost for each sample of €1048.32. This cost represents a crucial investment in terms of NSCLC patients survival, despite constituting only around 1% of the expenses incurred in their molecular diagnostic and therapeutic pathway. Conclusions: The cost comparison between NGS test and the notably higher therapeutic costs highlights that the diagnostic phase is not the limiting economic factor. Developing NGS facilities structured in pathology networks may ensure appropriate technical expertise and efficient workflows.

The biomarkers ATLAS: An audit on 1100 non-small cell lung cancer from an Italian knowledge-based database.

AIMS: To date, precision medicine has revolutionized the clinical management of Non-Small Cell Lung Cancer (NSCLC). International societies approved a rapidly improved mandatory testing biomarkers panel for the clinical stratification of NSCLC patients, but harmonized procedures are required to optimize the diagnostic workflow. In this context a knowledge-based database (Biomarkers ATLAS, https://biomarkersatlas.com/) was developed by a supervising group of expert pathologists and thoracic oncologists collecting updated clinical and molecular records from about 80 referral Italian institutions. Here, we audit molecular and clinical data from n = 1100 NSCLC patients collected from January 2019 to December 2020. METHODS: Clinical and molecular records from NSCLC patients were retrospectively collected from the two coordinating institutions (University of Turin and University of Naples). Molecular biomarkers (KRAS, EGFR, BRAF, ROS1, ALK, RET, NTRK, MET) and clinical data (sex, age, histological type, smoker status, PD-L1 expression, therapy) were collected and harmonized. RESULTS: Clinical and molecular data from 1100 (n = 552 mutated and n = 548 wild-type) NSCLC patients were systematized and annotated in the ATLAS knowledge-database. Molecular records from biomarkers testing were matched with main patients' clinical variables. CONCLUSIONS: Biomarkers ATLAS (https://biomarkersatlas.com/) represents a unique, easily managing, and reliable diagnostic tool aiming to integrate clinical records with molecular alterations of NSCLC patients in the real-word Italian scenario.

PIK3CA testing in hormone receptor-positive/HER2-negative metastatic breast cancer: real-world data from Italian molecular pathology laboratories.

Introduction: PIK3CA gene mutations occur in approximately 40% of hormone receptor-positive/HER2-negative (HR+/HER2-) metastatic breast cancers (MBCs), electing them to targeted therapy. Testing PIK3CA status is complex due to selection of biological specimen and testing method. Materials & methods: This work investigates real-life experience on PIK3CA testing in HR+/HER2- MBC. Clinical, technical and molecular data on PIK3CA testing were collected from two referral laboratories. Additionally, the results of a nationwide PIK3CA survey involving 116 institutions were assessed. Results: Overall, n = 35 MBCs were PIK3CA-mutated, with mutations mostly occurring in exons 9 (n = 19; 51.4%) and 20 (n = 15; 40.5%). The nationwide survey revealed significant variability across laboratories in terms of sampling methodology, technical assessment and clinical report signing healthcare figures for PIK3CA molecular testing in diagnostic routine practice. Conclusion: This study provides insights into the real-world routine of PIK3CA testing in HR+/HER2- MBC and highlights the need for standardization and networking in predictive pathology.

Interobserver variability in cytopathology: How much do we agree?

Interobserver variability remains a major challenge for cytopathologists despite the development of standardized reporting and classification systems. Indeed, whereas moderate-to-good interobserver agreement is generally achievable when the differential diagnosis between benign and malignant entities is straightforward, high levels of variability make the diagnostic interpretation of atypical and suspicious samples not consistent. This review explores the landscape of interobserver agreement in cytopathology across different anatomical sites.

Molecular testing in salivary gland cytopathology: A practical overview in conjunction with the Milan system.

Recently, significant advances in the molecular characterization of salivary gland neoplasms have facilitated the classification and diagnosis of specific diagnostic entities. In the highly challenging diagnostic scenario of salivary malignancies, molecular testing is increasingly being adopted in routine practice to refine the cytological diagnosis of salivary lesions. Here, we reviewed the most recent evidence in the field of salivary glands molecular cytopathology.

Non-Small Cell Lung Cancer Testing on Reference Specimens: An Italian Multicenter Experience.

INTRODUCTION: Biomarker testing is mandatory for the clinical management of patients with advanced non-small cell lung cancer (NSCLC). Myriads of technical platforms are now available for biomarker analysis with differences in terms of multiplexing capability, analytical sensitivity, and turnaround time (TAT). We evaluated the technical performance of the diagnostic workflows of 24 representative Italian institutions performing molecular tests on a series of artificial reference specimens built to mimic routine diagnostic samples. METHODS: Sample sets of eight slides from cell blocks of artificial reference specimens harboring exon 19 EGFR (epidermal growth factor receptor) p.E746_AT50del, exon 2 KRAS (Kirsten rat sarcoma viral oncogene homologue) p.G12C, ROS1 (c-ros oncogene 1)-unknown gene fusion, and MET (MET proto-oncogene, receptor tyrosine kinase) Δ exon 14 skipping were distributed to each participating institution. Two independent cell block specimens were validated by the University of Naples Federico II before shipment. Methodological and molecular data from reference specimens were annotated. RESULTS: Overall, a median DNA concentration of 3.3 ng/µL (range 0.1-10.0 ng/µL) and 13.4 ng/µL (range 2.0-45.8 ng/µL) were obtained with automated and manual technical procedures, respectively. RNA concentrations of 5.7 ng/µL (range 0.2-11.9 ng/µL) and 9.3 ng/µL (range 0.5-18.0 ng/µL) were also detected. KRAS exon 2 p.G12C, EGFR exon 19 p.E736_A750del hotspot mutations, and ROS1 aberrant transcripts were identified in all tested cases, whereas 15 out of 16 (93.7%) centers detected MET exon 14 skipping mutation. CONCLUSIONS: Optimized technical workflows are crucial in the decision-making strategy of patients with NSCLC. Artificial reference specimens enable optimization of diagnostic workflows for predictive molecular analysis in routine clinical practice.

The role of liquid biopsy in epithelial ovarian cancer: State of the art.

The clinical implementation of liquid biopsy has dramatically modified the analytical paradigm for several solid tumors. To date, however, only circulating free DNA (cfDNA) has been approved in clinical practice to select targeted treatments for patients with colorectal cancer (CRC), non-small cell lung cancer (NSCLC), and breast cancer (BC). Interestingly, emerging liquid biopsy analytes in peripheral blood, including circulating tumor cells (CTC), miRNA, and extracellular vesicles (EVs), have been shown to play a crucial role in the clinical management of solid tumor patients. Here, we review how these blood-based biomarkers may positively impact early diagnosis, prognosis, and treatment response in ovarian cancer (OC) patients.

Genomic profiling of tissue and blood predicts survival outcomes in patients with resected pleural mesothelioma.

PURPOSE: Pleural mesothelioma (PM) is an aggressive tumor still considered incurable, in part due to the lack of predictive biomarkers. Little is known about the clinical implications of molecular alterations in resectable PM tissues and blood. Here, we characterized genetic alterations to identify prognostic and predictive biomarkers in patients with resected PM. EXPERIMENTAL DESIGN: Targeted next-generation sequencing was performed in retrospective pleural tumor tissue and paired plasma samples from stage IB-IIIB resected PM. Association between prognosis and presence of specific mutations was validated in silico. RESULTS: Thirty PM tissues and paired blood samples from 12 patients were analyzed. High tissue tumor mutational burden (TMB) (>10 mutations/Mb), tissue median minor allele frequency (MAF) (>9 mutations/Mb), and blood TMB (>6 mutations/Mb), tissue KMT2C, PBRM1, PKHD1,EPHB1 and blood LIFR mutations correlated with longer disease-free survival and/or overall survival. High concordance (>80%) between tissue and blood was found for some mutations. CONCLUSIONS: Tissue TMB and MAF, blood TMB, and specific mutations correlated with outcomes in patients with resected PM and should be further studied to validate their role as prognostic biomarkers and potentially predictive factors for combinations with immune-checkpoint inhibitors. This suggest that molecular profiling could identify longer survivors in patients with resected PM.

The significance of tissue-agnostic biomarkers in solid tumors: the more the merrier?

INTRODUCTION: To date, several emerging biomarkers have gained considerable interest in the field of predictive molecular oncology. The advent of precision medicine has led to the development of innovative drugs targeting rare molecular pathways independently from histology, defined as tissue-agnostic drugs. AREAS COVERED: Although there is a lot of promise for this new tissue-agnostic model in the oncological scenario, crucial issues from both the diagnostic and therapeutic standpoint are emerging. This review aims to critically examine the role of tissue-agnostic biomarkers in different solid tumors, focusing on the prevalence and methods of detection of agnostic biomarkers together with drug approvals to guide clinicians in this evolving landscape. EXPERT OPINION: To strengthen the framework for tissue-agnostic approvals, the dialogue between regulatory, industrial, and academic parties should be intensified. Critical questions include the development of an efficient network system that can overcome the heterogeneity of patients' inclusion criteria along with the increasingly difficult interpretation of next-generation sequencing (NGS) profiling technologies. Cost-effectiveness and risk-benefit studies are needed in the national context considering the modalities of access to diagnostic tests and reimbursement of treatments.

Evaluating local thyroid cytopathology practices by molecular quality metrics: A multi-institutional study on 4651 FNAs with a focus on the role of the interventional cytopathologist.

BACKGROUND: The diagnostic accuracy of thyroid fine-needle aspiration (FNA) can be highly influenced by the technical skills of the operator performing the procedure and by interobserver variability in microscopic interpretation. This is particularly true for the indeterminate categories. Recently, molecular testing has been proposed as an ancillary tool for monitoring the performance of different thyroid cytopathology practices. The objective of this multicenter study was to evaluate the quality of different local cytopathology practices by assessing the impact of interventional cytopathologists on FNA adequacy for molecular testing and the variations in mutation rates across different health care centers operating in the Campania region. METHODS: The study included 4651 thyroid FNA samples diagnosed in different Southern Italian clinical laboratories belonging to the TIRNET (the Tiroide Network). FNA samples were collected by different proceduralists and were classified by local cytopathologists according to The Bethesda System for Reporting Thyroid Cytopathology. FNAs classified as atypia of undetermined significance, follicular neoplasm, suspicious for malignancy, and malignant were centralized for a real-time polymerase chain reaction-based, seven-gene test at the authors' institution. RESULTS: Centers that employed interventional cytopathologists obtained fewer unsatisfactory FNA samples for molecular testing (11.3%) than centers that employed noncytopathologists (16.7%; p < .05). Furthermore, a significant variation in the mutation rate was observed in FNAs diagnosed by different local cytopathologists; indeterminate categories had the highest percentage of mutation rate variability among centers. CONCLUSIONS: Interventional cytopathologists obtained higher yields of diagnostic material for molecular testing. Finally, the current results suggest that the variability in mutation rates among different centers may highlight the low reproducibility of microscopic criteria among cytopathologists, particularly for indeterminate cases.

An Italian Multicenter Perspective Harmonization Trial for the Assessment of MET Exon 14 Skipping Mutations in Standard Reference Samples.

Lung cancer remains the leading cause of cancer deaths worldwide. International societies have promoted the molecular analysis of MET proto-oncogene, receptor tyrosine kinase (MET) exon 14 skipping for the clinical stratification of non-small cell lung cancer (NSCLC) patients. Different technical approaches are available to detect MET exon 14 skipping in routine practice. Here, the technical performance and reproducibility of testing strategies for MET exon 14 skipping carried out in various centers were evaluated. In this retrospective study, each institution received a set (n = 10) of a customized artificial formalin-fixed paraffin-embedded (FFPE) cell line (Custom METex14 skipping FFPE block) that harbored the MET exon 14 skipping mutation (Seracare Life Sciences, Milford, MA, USA), which was previously validated by the Predictive Molecular Pathology Laboratory at the University of Naples Federico II. Each participating institution managed the reference slides according to their internal routine workflow. MET exon 14 skipping was successfully detected by all participating institutions. Molecular analysis highlighted a median Cq cut off of 29.3 (ranging from 27.1 to 30.7) and 2514 (ranging from 160 to 7526) read counts for real-time polymerase chain reaction (RT-PCR) and NGS-based analyses, respectively. Artificial reference slides were a valid tool to harmonize technical workflows in the evaluation of MET exon 14 skipping molecular alterations in routine practice.

Multiple predictive biomarker testing in melanoma: Another challenge in identifying the optimal approach on cytological samples.

BACKGROUND: The management of cutaneous melanoma has changed dramatically in recent years thanks to the development of tyrosine kinase and immune-checkpoint inhibitors (ICIs). Thus, multiple biomarker testing is becoming ever more important for the identification of patients who are potentially eligible for these treatments. One reliable approach to the molecular evaluation of metastatic melanoma is fine needle cytology (FNC). To examine the utility of this approach for assessing PD-L1 expression levels, we evaluated the cellular adequacy of residual cell block (CB) material from metastatic melanomas that were previously tested for BRAF and NRAS mutations. METHODS: We retrieved from our internal archives a series of FNC samples of metastatic melanoma that had been subjected to molecular testing on residual CB material or a dedicated needle rinse between January 2016 and July 2022. Real-time polymerase chain reaction was used to assess BRAF and NRAS status, and an SP263 assay was employed to ascertain PD-L1 expression levels. RESULTS: Overall, n = 19 cases were selected. Of these, 11 (57.9%) cases revealed a BRAF exon 15 p.V600E mutation, one case (5.3%) revealed NRAS mutation, and seven cases (36.8%) showed no mutations. Regarding PD-L1 assessment, 16/19 (84.2%) cases were deemed adequate, meaning they contained at least 100 viable cells. CONCLUSIONS: We highlighted the feasibility of assessing PD-L1 expression levels in residual CB material from metastatic melanomas previously tested for BRAF and NRAS mutations. Moreover, we pointed out that FNC needle rinses may be an alternative source of nucleic acids for molecular testing, preserving CB material for immunocytochemistry evaluation.

Reference standards for gene fusion molecular assays on cytological samples: an international validation study.

AIMS: Gene 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. METHODS: Cell 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. RESULTS: Four (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. CONCLUSIONS: Reference 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.

Comparison of two next-generation sequencing-based approaches for liquid biopsy analysis in patients with non-small cell lung cancer: a multicentre study.

In the era of personalised medicine, testing for an increasing number of predictive biomarkers is becoming a priority. However, tissue biopsies from these patients are oftentimes insufficient for conventional approaches, a common issue that deprives them of the clinical benefits of biomarker-directed treatments. To tackle this problem, many clinical laboratories are resorting to circulating tumour DNA (ctDNA), which is becoming increasingly appreciated as a valuable source for biomarker testing. In this context, next-generation sequencing (NGS) has become essential. Indeed, different NGS systems are able to detect several clinically relevant low-frequency hot-spot mutations simultaneously in a single run. However, their reproducibility in the analysis of ctDNA has not yet been investigated. The purpose of this study was to evaluate the reproducibility of using Illumina MiSeq and Thermo Fisher Ion S5 Plus platforms to assess pathogenic alterations in non-small cell lung cancer (NSCLC) liquid biopsy specimens. Using the in vitro diagnostic (IVD) NGS panel Myriapod NGS Cancer panel DNA (Diatech Pharmacogenetics) on MiSeq platform (Illumina), we reanalysed ctDNA extracted from a retrospective series of n=40 patients with advanced NSCLC previously tested with a custom NGS panel (SiRe) on Thermo Fisher Ion S5 Plus system. Overall, 13 out of 40 (32.5%) ctDNA samples displayed pathogenic alterations in at least two genes, namely, EGFR and KRAS A concordance rate of 100% was identified between the two methodologies in terms of sample mutational status and total number of detected variables. All NGS platforms featured a high degree of concordance.

Microsatellite instability evaluation of patients with solid tumour: routine practice insight from a large series of Italian referral centre.

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.