Resumo

JIMENEZ-JIMENEZ, Geiner; SAUMA-RODRIGUEZ, Johanna; ABBAS-CHAKTOURA, Jad  e  SANTAMARIA QUESADA, Carlos. DNA Mismatch Repair deficiency in colorectal adenocarcinoma: an evaluation test for suspecting Lynch Syndrome. Acta méd. costarric [online]. 2024, vol.66, n.1, pp.8-17. ISSN 0001-6002.

Aim: To profile the clinical and pathological characteristics and determine the prevalence of defective deoxyribonucleic acid mismatch repair using immunohistochemistry in individuals diagnosed with colon adenocarcinoma at the age of < 70 years. Additionally, to compare the detection of suspected Lynch syndrome cases using immunohistochemistry in all patients versus only those meeting clinical and pathological suspicion criteria.

Methods: An observational, cross-sectional study involving 249 patients was conducted. The study analyzed demographic characteristics, personal and family history of cancer, compliance with Amsterdam, Bethesda, and PREMM5 criteria, as well as pathological characteristics of colorectal adenocarcinoma. The prevalence of immunohistochemical alterations in MLH1, MSH2, MSH6, and PMS2 proteins indicative of suspected Lynch syndrome was determined, and the probability and concordance of finding these alterations based on clinical and pathological variables were estimated.

Results: In this sample, immunohistochemistry identified 22 cases (8.8%) with alterations suggestive of Lynch syndrome. None of these cases fully met the clinical and pathological suspicion criteria for the syndrome. Most participants meeting the suspicion criteria did not show immunohistochemical alterations. A higher prevalence of immunohistochemical alterations was observed in right-sided cancer (proximal to the splenic flexure) and in cases meeting Bethesda criteria 3 or 4. The agreement between clinical criteria and immunohistochemistry was found to be minimal to low.

Conclusion: These findings suggest that immunohistochemistry screening in patients with colorectal adenocarcinoma could identify more candidates for further studies to confirm Lynch syndrome, independent of the clinical and pathological criteria typically used to select patients for immunohistochemistry testing.

Palavras-chave : Colorectal neoplasm; Neoplastic Syndromes; Hereditary; DNA mismatch repair deficiency; microsatellite instability; Lynch Syndrome.

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