MKI67 and breast cancer: The neoMONARCH trial evaluating the biological and clinical activity of combined neoadjuvant abemaciclib and anastrozole in postmenopausal women with stage I-IIIB HR + /Her2- breast cancer demonstrated increased rates of complete cell-cycle arrest and decrease in Ki67, with 46% of intention-to-treat patients achieving a radiologic response [17].