Mismatch repair status in sporadic colorectal cancer: Immunohistochemistry and microsatellite instability analyses

Abstract

Patients with MMR defects had distinct clinicopathological characteristics, including a lower risk of recurrence. IHC and MSI analyses provided complementary information regarding specific clinicopathological parameters and prognosis.

DNA Mismatch Repair Deficiency in Colorectal Adenocarcinoma and its Association with Clinicopathological Features

“…According to our results, patients with dMMR status had distinct clinicopathologic features, including younger age, larger tumor size, more likely right-colon location, mucinous-focal or signet-ring histological phenotype, poor differentiation and more common occurrence in stage . These findings generally agreed with previous reports [8,12]. Whereas, we did not demonstrate that there was significant association between dMMR status and mucinous carcinomas, of which only 2 cases (2/23, 8.7%) showed MMR deficiency.…”

“…And then the specificity of IHC in predicting MSI-H would reach 100% like what the previous reports published [14]. When distinct nuclear staining of more than 10% of all nuclei was defined as positive staining, the sensitivity was 63.1%, and the specificity was 95.7% [8]. Secondly, in our study, rectum cancer (262/481, 54.5%) accounted for more than half of all cases' onsets and only 5 of them (5/262, 1.9%) had defective MMR protein expression.…”

“…Finally, an alternative possibility was due to racial differences between the Asian and the Western populations. In Korea, IHC identified 10.2% tumor samples with a loss of either MLH1 or MSH2 expression and MSI analysis identified 10% tumor samples with high-frequency in 2028 patients [8]. However, in America and Europe, approximately 15% of CRCs exhibit MSI-H [9,12,13,18,19,].…”

“…Previous studies have revealed distinct clinicopathologic features of dMMR tumors, such as poor differentiation, abundant mucin secretion, marked lymphocytic infiltration, preferential location in the proximal colon and association with a favorable prognosis [7][8][9][10][11][12]. Until now, data on the role of MMR status in Chinese patients with CRC are scarce and the relationship between MMR status and clinicopathologic features is also uncertain.…”

Microsatellite instability: Detection and management in sporadic colorectal cancer

“…8 Critical to the findings of any such studies are the methods used to identify MSI cancers and the protocols in place to select a homogeneous study population. Immunohistochemical staining for mismatch repair proteins is inexpensive and offered routinely in pathology laboratories.…”