RT Journal Article SR Electronic T1 Multi-gene custom panels for the characterisation of metastatic colorectal carcinoma in clinical practice: express the role of PIK3CA mutations JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP jclinpath-2021-207468 DO 10.1136/jclinpath-2021-207468 A1 Dario de Biase A1 Umberto Malapelle A1 Antonio De Leo A1 Thais Maloberti A1 Michela Visani A1 Pasquale Pisapia A1 Giorgia Acquaviva A1 Francesco Pepe A1 Gianluca Russo A1 Antonino Iaccarino A1 Annalisa Pession A1 Giovanni Tallini A1 Giancarlo Troncone YR 2021 UL http://jcp.bmj.com/content/early/2021/04/04/jclinpath-2021-207468.abstract AB Aims In metastatic colorectal carcinomas (mCRC), RAS/RAF genes mutations are first tested to determine the eligibility for anti-EGFR (Epidermal Growth Factor Receptor) therapy in combination with conventional cytotoxic agents. Recent advancements in next-generation sequencing (NGS) have highlighted the potential of multi-gene panels. This multi-gene analysis may provide useful information for the molecular characterisation of mCRC, other than the status of RAS/RAF genes. Aim of this study was to evaluate the feasibility of two NGS custom multi-gene panels in the characterisation of CRC cases and evaluating the relevance of PIK3CA mutation in a routine cohort of consecutive CRC cases.Methods A total of 961 formalin-fixed and paraffin-embedded specimens from two medical centres (Bologna and Naples) were analysed using two lab-developed NGS multi-gene panels.Results KRAS mutations (56.2%) were the more frequent alterations observed in our cohort. Intriguingly, PIK3CA mutations were more frequent (16.8%) than variants observed in the other two genes nowadays analysed in CRC clinical practice (NRAS and BRAF, 4.2% and 9.6%, respectively). Moreover, in more than 10% of samples, coexistent mutations were detected in our cohort of CRC.Conclusions Our study demonstrates the feasibility and efficacy of lab-developed targeted multi-gene NGS panels in the clinical practice of CRC. Moreover, the data lead to hypothesise that PIK3CA mutations, together with those of RAS/BRAF, worth to be further investigated in clinical CRC specimens.All data relevant to the study are included in the article or uploaded as supplementary information.