Differential Effect of Polymorphisms of CMPK1 and RRM1 on Survival in Advanced Non-small Cell Lung Cancer Patients Treated with Gemcitabine or Taxane/Cisplatinum

Introduction: To determine whether genetic variations in CMPK1 or RRM1, which impact the pharmacodynamics of gemcitabine, differentially affect the outcomes of non-small cell lung cancer (NSCLC) patients treated with gemcitabine or taxane/cisplatinum. Methods: We conducted retrospective study evaluating the associations between overall survival in 298 NSCLC patients at stages IIIA/IIIB (140) and IV (158), treated with gemcitabine (139) or taxane (159)/cisplatinum and 14 tagging single-nucleotide polymorphisms (tSNPs): 4 in CMPK1 and 10 in RRM1. Results: The wild-type genotypes of CMPK1 IVS1 + 1057 and IVS1 - 928 were associated with shorter overall survival in patients treated with the gemcitabine/cisplatinum (adjusted hazards ratio = 1.97 and 1.89; Cox p(Bonferroni) = 0.008 and 0.020), whereas this effect was not observed in patients treated with taxane/cisplatinum. No associations were observed for the other 2 CMPK1 or 10 RRM1 tSNPs. Analysis of the interaction between the CMPK1 and RRM1 genes showed that the survival of patients with CMPK1 IVS1 + 1057 CC and RRM1 IVS1 - 2374 TT, IVS7 + 25 AA, IVS7 - 425 AA, or IVS8 + 287 TT was significantly shorter when they were treated with the gemcitabine/cisplatinum (adjusted hazards ratio = 3.00, 2.89, 3.14, and 3.00; Cox p(Bonferroni) = 0.007, 0.012, 0.006, and 0.007). However, these effects were not observed in patients treated with taxane/cisplatinum. Conclusions: These findings suggest that polymorphisms of CMPK1 and their combination with those of RRM1 are helpful in identifying patients who will benefit less from a gemcitabine/cisplatinum as the first-line regimen.