{Reference Type}: Journal Article
{Title}: Mismatch repair protein deficiency in triple-negative breast carcinomas.
{Author}: Maraqa B;Al-Ashhab M;Zughaier H;Barakat F;Khader M;Al Maaitah H;Alabweh R;Sughayer M;
{Journal}: J Int Med Res
{Volume}: 52
{Issue}: 6
{Year}: 2024 Jun
{Factor}: 1.573
{DOI}: 10.1177/03000605241259747
{Abstract}: <B>BACKGROUND: </B>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.<BR><B>METHODS: </B>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.<BR><B>RESULTS: </B>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.<BR><B>CONCLUSIONS: </B>Approximately 9% of TNBC patients exhibit dMMR. dMMR could be used to predict outcomes and identify patients with TNBC who may benefit from immunotherapy.