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Is elevated microsatellite alterations at selected tetranucleotide repeats (EMAST)‐negative/MSI‐high colorectal cancer a distinct subtype of the disease?
Author(s) -
Park Yeshong,
Kim DuckWoo,
Hong Yun Ji,
Park Kyoung Un,
Nam Soo Kyung,
Na Hee Young,
Lee Hye Seung,
Kim Min Hyun,
Oh HeungKwon,
Kang SungBum
Publication year - 2020
Publication title -
journal of surgical oncology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.201
H-Index - 111
eISSN - 1096-9098
pISSN - 0022-4790
DOI - 10.1002/jso.26157
Subject(s) - medicine , microsatellite instability , oncology , colorectal cancer , retrospective cohort study , immunohistochemistry , microsatellite , cancer , gene , genetics , allele , biology
Abstract Background and Objectives Microsatellite instability (MSI) plays a prognostic and predictive role in colorectal cancer (CRC). Elevated microsatellite alterations at selected tetranucleotide repeats (EMAST), a novel type of MSI, was recently identified. Methods A retrospective analysis of a prospective cohort database was performed. Patients who attempted curative surgery for MSI‐high (MSI‐H) CRC and had available testing results of EMAST were included for analysis. The difference in clinical characteristics, immunohistochemistry profile, and 3‐year recurrence‐free and overall survival between EMAST‐negative and EMAST‐positive tumors was measured. Results EMAST status was successfully evaluated in 86 cases among patients who received EMAST testing, and only 16.3% (14/86) of these patients were EMAST‐negative/MSI‐H. Patients with EMAST‐negative tumors were younger; their tumors exhibited well differentiation, less venous invasion, and greater mutS homolog 3 expression. There was no distant metastasis or cancer‐specific death among EMAST‐negative patients. Yet no statistically significant difference was found between the two groups in 3‐year overall or recurrence‐free survival. Conclusions Patients with EMAST‐negative/MSI‐H CRC seem to have different clinicopathological characteristics. Future large‐scale studies could clarify the role of EMAST genotype as a sub‐classifier of MSI‐H CRC.