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CC BY 4.0 · Journal of Coloproctology 2025; 45(04): s00451813741
DOI: 10.1055/s-0045-1813741
Original Article

Immunohistochemical Assessment of MLH1, MSH2, MSH6, and PMS2 Expression and Mismatch Repair Deficiency in Surgically Resected Colorectal Carcinomas

Autor*innen

  • Gustavo Sevá-Pereira

    1   Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil

  • Carlos Augusto Real Martinez

    2   Universidade São Francisco (USF), Bragança Paulista, SP, Brazil

  • Jose Aires Pereira

    2   Universidade São Francisco (USF), Bragança Paulista, SP, Brazil

  • Poliana Pacciulli Pereira

    2   Universidade São Francisco (USF), Bragança Paulista, SP, Brazil

  • Geovanna Pacciulli Pereira

    2   Universidade São Francisco (USF), Bragança Paulista, SP, Brazil

  • Claudio Saddy Rodrigues Coy

    1   Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
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Abstract

Background

Deficiency of DNA mismatch repair (dMMR) in colorectal cancer (CRC) predicts prognosis and guides' therapy. Data on dMMR prevalence and predictors in Brazil remain limited.

Objective

To estimate the prevalence of dMMR in CRC resections and identify independent clinical-pathological predictors.

Materials and Methods

We retrospectively analyzed 330 adults who underwent resection for primary colorectal adenocarcinoma between January 2008 and December 2024 at a public hospital and a private clinic in Campinas, in the state of São Paulo, Brazil. The exclusion criteria were non-adenocarcinoma histology, complete pathologic response to neoadjuvant therapy, inflammatory bowel disease-associated CRC, polyposis syndromes, and inadequate tissue. Immunohistochemistry (IHC) for MLH1, MSH2, MSH6, and PMS2 was centralized; complete loss of any protein indicated dMMR. We recorded age, sex, tumor site, histological grade, and nodal status. Univariate analyses used the Fisher's exact and Mann-Whitney tests, and a multivariable logistic regression was conducted to identify independent dMMR predictors (p  <  0.05).

Results

The dMMR prevalence was 12.7% (42/330). In the multivariable analysis, proximal location (odds ratio [OR]: 2.51; 95%CI: 1.26–4.99; p  =  0.009) and high grade (OR: 3.79; 95%CI: 1.40–6.24; p  =  0.008) were independently associated with dMMR, but age was not (p  =  0.441). Node-positive tumors had higher dMMR rates than node-negative cases (17.1 % versus 11.0 %; p  =  0.045). The predominant IHC profile was MLH1 + PMS2 co-loss (47.6 % of dMMR cases).

Conclusions

Approximately one in eight CRCs in this Brazilian cohort is positive for dMMR. Tumor phenotype (proximal site, poor differentiation), rather than age, predicts dMMR.

Keywords

colorectal cancer - MMR - immunotherapy - colorectal surgery - MSI

Authors' Contributions




Publikationsverlauf

Eingereicht: 04. Oktober 2024

Angenommen: 04. August 2025

Artikel online veröffentlicht:
31. Dezember 2025

© 2025. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution 4.0 International License, permitting copying and reproduction so long as the original work is given appropriate credit (https://creativecommons.org/licenses/by/4.0/)

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Bibliographical Record
Gustavo Sevá-Pereira, Carlos Augusto Real Martinez, Jose Aires Pereira, Poliana Pacciulli Pereira, Geovanna Pacciulli Pereira, Claudio Saddy Rodrigues Coy. Immunohistochemical Assessment of MLH1, MSH2, MSH6, and PMS2 Expression and Mismatch Repair Deficiency in Surgically Resected Colorectal Carcinomas. Journal of Coloproctology 2025; 45: s00451813741.
DOI: 10.1055/s-0045-1813741