Colorectal cancer with mucinous component compared to clinicopathological and molecular features as mucinous adenocarcinoma.

Abstract

e15166 Background: CRC can be divided into 3 groups: regular adenocarcinoma (RA), mucinous adenocarcinoma (MA), and adenocarcinoma with mucinous component (MC, mucin formation <50 % ). MA is distinct from RA, however, little is known about MC. We aimed to compare the clinicopathological and genetic features of 3 groups. Methods: A retrospective chort of consecutive CRC patients with available gene status was enrolled. KRAS,NRAS,BRAF,PIK3CA gene, MSI(IHC method) status were analyzed. Results: A total of 1454 patients were enrolled, including 1179 RA, 106 MA and 169 MC. Similar to MA, MC patients were younger, tended in proximal colon, had more advanced T stage ,higher nodal and peritoneal metastasis compared to RA. MSI-H were more occurred in MA and MC than RA (18.9%, 15.1% vs.3.9%). MC and MA had identical mutation frequency.They had higher KRAS (62.1%,62.3% vs.41.4%), BRAF(10.1%,9.4% vs.1.9%) and PIK3CA(21.3%,21.7% vs.9.4%) mutation than RA. Among MA or MC patients, almost 80% had at least one mutation, 17% had double mutation,and the mutation rates between left and right colon was similar, which is distinguish from RA. Conclusions: MC has comparable patholgical and molecular features as MA, which is distinct from RA. We should consider mucinous histology and the genetic features into future clinical practice. [Table: see text]