TUMOR MUTATIONAL BURDEN (TMB) IS A POTENTIAL PREDICTOR OF RESPONSE TO IMMUNE CHECKPOINT INHIBITORS (ICI) IN METASTATIC TRIPLE-NEGATIVE BREAST CANCER (MTNBC) - Barroso-Sousa, Romualdo; Tyekucheva, Svitlana; Exman, Pedro; Umeton, Renato; Hodi, F. Stephen; Winer, Eric P.; Lin, Nancy U; Tolaney, Sara M. (Mastology, 2019)