To better understand cellular reactions to metronomic chemoendocrine therapy, we studied autophagy-related markers, beclin 1 and LC3, and apoptosis-related markers, TUNEL and M30, in pre- and post-treatment cancer tissues from a multicenter neoadjuvant trial, JBCRG-07, in which oral cyclophosphamide plus letrozole were administered to postmenopausal patients with HR-positive breast cancer. This evidence concerns the gene BECN1 and breast cancer.