Effects of single nucleotide polymorphisms of the folylpolyglutamate synthase gene on pemetrexed administration-induced nephropathy

Long-term administration of pemetrexed (PEM) in patients with lung cancer can cause renal damage, leading to treatment discontinuation. Previous reports have suggested that specific single nucleotide polymorphisms (SNPs) in the folylpolyglutamate synthase (FPGS) gene affect therapeutic efficacy; however, whether the FPGS SNPs affect renal function is unclear. Identifying SNPs related to renal damage during PEM administration may help predict the decrease in renal function caused by PEM.

We retrospectively examined age, sex, body weight, total administered PEM, combined platinum, estimated glomerular filtration rate (eGFR) and serum creatinine (SCr) levels before and after PEM administration in patients with non-small cell lung cancer and searched for the alleles of FPGS SNPs (rs1544105 and rs10106) using DNA extracted from whole blood samples of patients.

Renal function decreased after PEM administration in 26 cases overall. The SCr and eGFR indices showed decreased renal function irrespective of concomitant cisplatin use. Based on promoter activity and miRNA binding predictions, rs1544105-C and rs10106-T were hypothesized to increase FPGS expression. Single SNP analyses showed no significant differences in renal function between groups with and without each SNP. Multiple regression analysis revealed that the most significant factors for decreased renal function were sex on SCr and the number of SNPs on eGFR. In subgroup analyses, the patients with rs10106-T showed a decline in renal function in the older group.

The number of FPGS SNPs may contribute to PEM-induced renal impairment. Detecting FPGS SNPs may help predict PEM-induced renal damage.