Mucinous carcinomas of the colon and rectum show higher rates of microsatellite instability and lower rates of chromosomal instability

Abstract

BACKGROUNDThe clinicopathologic significance of mucinous carcinomas (Muc) of the colon and rectum has been widely discussed, but there have been few studies on Muc regarding genetic and epigenetic alterations. The current study analyzed genetic and epigenetic alterations of Muc to clarify their differences from well differentiated adenocarcinomas (WD).METHODSThirty‐nine cases of Muc and 39 cases of WD were investigated. Cases of WD were matched with cases of Muc for T classification and tumor location. Microsatellite instability (MSI) status and loss of heterozygosity (LOH) of four loci (2p, 5q, 17p, 18q) were evaluated. The methylation status of the hMLH1 promoter region in Muc was also examined.RESULTS“MSI tumors” were defined as those that showed MSI‐high, and “chromosomal instability (CIN) tumors” were defined as those that showed LOH but not MSI‐high. MSI tumors were significantly more frequent in Muc (30.8%) than in WD (5.1%). CIN tumors were significantly less frequent in Muc (53.8%) than in WD (87.2%). In Muc, MSI tumors were significantly more frequent in the proximal colon (55.6%) than in the distal colon (9.5%). Also, methylation of the hMLH1 promoter region in Muc was significantly more frequent in MSI tumors (83.3%) than in CIN tumors (27.8%) (P = 0.0077).CONCLUSIONSWhen matched for T classification and tumor location, Muc shows higher rates of MSI and lower rates of CIN than WD.. Muc shows different characteristics according to tumor location, and methylation of the hMLH1 promoter region strongly correlates with Muc tumors showing MSI. Cancer 2005. © 2005 American Cancer Society.

Clinicopathological characteristics, microsatellite instability, and expression of mucin core proteins and p53 in colorectal mucinous adenocarcinomas in relation to location

“…In their study, 41.4% of right-sided mucinous carcinomas were MSI-H compared to 11.8% of left-sided mucinous carcinomas. Recently, Kazama et al [17] also showed that in mucinous carcinoma, MSI tumors were significantly more frequent in the proximal colon (55.6%) than in the distal colon (9.5%). Thus, although mucinous histology is a characteristic feature of MSI-H colorectal cancers, this does not apply to left-sided MAs.…”

A Matched Case-Control Study Using the Propensity Score on Differences in the Characteristics of Colorectal Polyps between Younger and Older Koreans: Proximal Shift in the Distribution of Colorectal Polyps among Older Koreans

“…Histopathological and morphological differences have been reported between proximal and distal colon cancer. 17,18 Moreover, epidemiological studies have revealed that the clinical risk factors for cancer development are also different between proximal and distal colon cancer. 13,19 However, the reasons for these differences between left-and right-sided cancer remain unknown.…”

Age-related methylation in normal colon mucosa differs between the proximal and distal colon in patients who underwent colonoscopy

“…Proximal colon cancer is frequently observed in older people and in women, while distal colon cancer is dominant in relatively young people and in men [31,32]. Histopathological and morphological differences have been reported between proximal and distal colon cancer [33][34][35]. Genetic and epigenetic alterations also differ.…”