The final results of a randomized phase two study reported a statistically significant improvement of the median progression free survival (PFS) of 20.2 months for women with ER+ stage IV breast cancer treated with combination of palbociclib (CDK4/6 inhibitor) plus letrozole compared to 10.2 months of PFS for women who received letrozole alone [6]. The gene discussed is CDK4; the disease is breast carcinoma.