CHEK1 and non-small cell lung carcinoma: The formation of gemcitabine resistance in NSCLC may involve multiple mechanisms, including mutations in drug targets, upregulation of drug-metabolizing enzymes, enhanced DNA repair ability, and changes in cell cycle regulation.28 Among them, CHK1, as a key cell cycle checkpoint kinase, is crucial in maintaining genomic stability and promoting DNA damage repair.29 Our research results indicate that inhibition of CHK1 can enhance the killing effect of gemcitabine on drug-resistant NSCLC cell lines.