RESUMEN

BACKGROUND: Breast cancer, particularly triple-negative breast cancer (TNBC), poses a significant global health burden. Chemotherapy was the mainstay treatment for TNBC patients until immunotherapy was introduced. Studies indicate a noteworthy prevalence (0.2% to 18.6%) of mismatch repair protein (MMRP) deficiency in TNBC, with recent research highlighting the potential of immunotherapy for MMRP-deficient metastatic breast cancer. This study aims to identify MMRP deficiency in TNBC patients using immunohistochemistry. METHODS: A retrospective cohort study design was used and included TNBC patients treated between 2015 and 2021 at King Hussein Cancer Center. Immunohistochemistry was conducted to assess MMRP expression. RESULTS: Among 152 patients, 14 (9.2%) exhibited deficient MMR (dMMR). Loss of PMS2 expression was observed in 13 patients, 5 of whom showed loss of MLH1 expression. Loss of MSH6 and MSH2 expression was observed in one patient. The median follow-up duration was 44 (3-102) months. Despite the higher survival rate (80.8%, 5 years) of dMMR patients than of proficient MMR patients (62.3%), overall survival did not significantly differ between the two groups. CONCLUSION: Approximately 9% of TNBC patients exhibit dMMR. dMMR could be used to predict outcomes and identify patients with TNBC who may benefit from immunotherapy.

Asunto(s)

Reparación de la Incompatibilidad de ADN , Proteínas de Unión al ADN , Endonucleasa PMS2 de Reparación del Emparejamiento Incorrecto , Neoplasias de la Mama Triple Negativas , Humanos , Femenino , Neoplasias de la Mama Triple Negativas/genética , Neoplasias de la Mama Triple Negativas/patología , Neoplasias de la Mama Triple Negativas/metabolismo , Persona de Mediana Edad , Adulto , Estudios Retrospectivos , Endonucleasa PMS2 de Reparación del Emparejamiento Incorrecto/metabolismo , Endonucleasa PMS2 de Reparación del Emparejamiento Incorrecto/genética , Anciano , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Homólogo 1 de la Proteína MutL/metabolismo , Homólogo 1 de la Proteína MutL/genética , Proteína 2 Homóloga a MutS/metabolismo , Biomarcadores de Tumor/metabolismo , Biomarcadores de Tumor/genética , Tasa de Supervivencia , Inmunohistoquímica , Anciano de 80 o más Años , Pronóstico