Background: Molecular testing is increasingly needed in colorectal carcinoma (CRC) and the current clinically relevant mutations are in BRAF, KRAS and NRAS. This study aimed to further validate a new alternative polymerase chain reaction (PCR) platform (Idylla, Biocartis) against existing next-generation sequencing (NGS) and immunohistochemistry (IHC) assays.
Methods: 56 Idylla tests were performed on 43 CRC cases, in a total of 74 comparisons against an NGS panel (Ion Torrent) and the VE1 (anti-BRAF) antibody IHC. Discrepant cases were also compared with either conventional (Cobas) or droplet digital PCR (Bio-Rad).
Results: Idylla showed an overall concordance of 100% (95% CI 93% to 100%) with comparator molecular testing and indications were that Idylla is likely to be more sensitive than routine NGS. BRAF IHC showed 90% concordance with NGS (95% CI 70% to 97%).
Conclusions: This study validates Idylla in formalin-fixed, paraffin-embedded CRC tissue. BRAF IHC, however, is an unreliable substitute for molecular testing in CRC.
Keywords: COLORECTAL CANCER; IMMUNOHISTOCHEMISTRY; MOLECULAR PATHOLOGY.
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