Concerning sex-specific treatment strategies, we found sex differences in genes previously identified in OS with therapies approved or in clinical trials for other cancers including CDK4 [12] in soft tissue sarcomas and breast cancers; LCK [16, 25] in sarcomas and hematologic malignancies; ROS1 [16, 25] in soft tissue sarcomas and neuroendocrine tumors; FLT3 [16] in hematologic malignancies and other cancers; and, TP53, which is commonly mutated in OS and has a drug in phase 3 trials for myelodysplastic syndrome [12]. The gene discussed is CDK4; the disease is breast cancer.