The expression of genes on chromosome 20q defines the mucinous characteristic of colorectal cancer

Abstract

Colorectal mucinous adenocarcinoma (MAC) is one of the poorest prognostic types of histological diagnoses, and its mechanism of development is not well understood. In this study, we aimed to clarify the molecular characteristics of MAC from the perspective of chromosomal instability. In silico analysis using The Cancer Genome Atlas database revealed that there was a significant difference in copy number alteration of chromosome 20q (Chr20q) between MAC and nonmucinous adenocarcinoma (NMAC). In addition, the expression of genes on Chr20q was negatively associated with the expression of MUC2, which is a key molecule that can be used to distinguish the two histological types. We further identified 475 differentially expressed genes (DEGs) between MAC and NMAC, and some of the Chr20q genes in DEGs are considered to be pivotal genes used to define MAC. In vitro analysis showed that simultaneous knockdown of POFUT1 and PLAGL2, both of which are located on Chr20q, attenuated MUC2 expression. Moreover, these genes were highly expressed in NMAC but not in MAC according to the results of immunohistological studies using human samples. In conclusion, the genes on Chr20q are considered to be important for defining MAC.