Molecular characteristics and prognostic implication of mucinous histology in colorectal cancer patients treated with adjuvant FOLFOX.

3550 Background: There have been controversies in prognostic impact of mucinous histology in colorectal cancer (CRC) and its implication in pts treated with adjuvant FOLFOX is unclear. This study aimed at elucidating the molecular characteristics and prognostic implication of mucinous histology in pts treated with adjuvant FOLFOX. Methods: Stage II and III CRC pts who received adjuvant FOLFOX were analyzed. Pts were grouped according to the mucinous content: > 50%, mucinous adenocarcinoma (MAC); < 50%, adenocarcinoma with intermediated mucinous component (AIM); and without any mucinous component, nonmucinous adenocarcinoma (NMA). Clinicopathologic features, MSI status (N = 518), CpG island methylator phenotype (CIMP) (N = 322) BRAF mutation (N = 269) and disease-free survival (DFS) were compared. Results: Among a total of 521 pts, 27 (5.2%) had MAC, 41 (7.9%) AIM, and 453 (86.9%) NMA. MAC and AIM had higher frequency of proximal location and lower angiolymphatic invasion. MAC had higher proportion of T4 t...