CMPK1 and breast cancer: Extensive research has been conducted to investigate the correlation between genetic polymorphisms and the clinical effectiveness of gemcitabine across diverse patient cohorts, including those with lung, pancreatic, and breast cancer.[10, 11, 12, 13, 14] Notably, studies in pancreatic cancer patients have revealed a link between the CMPK1 gene polymorphism and the survival rate after gemcitabine therapy.[15]