Molecular subtypes in early colorectal cancer associated with clinical features and patient prognosis.
Mireia Gil RagaE Jantus-LewintreS GallachV Giner-BoschA Frangi-CaregnatoM J Safont-AguileraJ Garde-NogueraE Zorraquino-PinaM García-MartínezC Camps-HerreroPublished in: Clinical & translational oncology : official publication of the Federation of Spanish Oncology Societies and of the National Cancer Institute of Mexico (2018)
RAS and BRAFV600E mutations were detected in 43.8 and 11.4% of patients, respectively. 19% of tumours had lack of expression of any MMR proteins reflecting a system deficiency (dMMR). Patients with any RAS mutation had lower DFS that patients with RAS wild type (wt) (40.23 vs 45.26 months; p value = 0.035). Of a total of five molecular subtypes, three were MMR proficient (pMMR): RAS mutated (39%), BRAFV600E mutated (6.7%) and RAS/BRAFV600E wt (35.2%); and two were dMMR: BRAFV600E mutated (4.8%) and BRAFV600E wt (14.3%). Left side tumours were more frequently observed in pMMR/RAS and BRAFV600E wt subtype, and right side tumours in dMMR subtypes. Among the three pMMR subtypes, a benefit survival was observed for patients without any mutation in BRAFv600E or RAS oncogenes (median of DFS = 45.5 vs 40.98 months in RAS mutated group; p = 0.084 and vs 34.13 in BRAFv600E mutated group; p = 0.031). Molecular classification using these biomarkers can be useful to identify groups with differences in prognosis.