Single nucleotide polymorphisms (SNPs) of the platinum pharmacogenetic and VEGF pathways: Association with survival of platinum-treated stage IV non-small cell lung cancer (NSCLC) patients.

Abstract

7586 Background: Two potentially important host pathways in lung cancer systemic therapy are: (i) the pharmacogenetic pathway of platinum agents (DNA repair, metabolism, and multidrug resistance genes); and (ii) the vascular endothelial growth factor (VEGF) pathway. We investigated the relationship between SNPs in these two pathways and clinical outcome in platinum-treated NSCLC patients. Methods: 188 platinum-treated Stage IV NSCLC patients underwent SNP genotyping for the platinum-related (48 SNPs in 7 genes) and VEGF (64 SNPs in 3 genes) pathways. SNPs were selected from the literature and through tagging. Association of SNPs and overall (OS) and progression free survival (PFS) were assessed using multivariate Cox proportional hazards models. Results: 72% were Caucasian; 73%, adenocarcinoma; 92%, ECOG PS 0-1; median age, 60 years; 54% received > one line of systemic therapy; 10% received anti-VEGF therapy/placebo; Median OS, 1.3 yrs; median follow up, 2.2 yrs. The top significant SNPs in the platinum-related pathway were in ABCC2 (rs8187710 and rs2756109, r2=0.68). The G variants of the top SNP, ABCC2 rs8187710 (4554G>A), were associated with worse OS (adjusted hazard ratio [aHR], 2.62; 95%CI: 1.5-4.5; p=0.0005) and PFS (aHR, 1.97; 95%CI: 1.2-3.4; p=0.01). Functionally, 4554G>A impairs ATP-ase activity and is associated with higher cellular accumulation of ABCC2 substrates [PMID: 22027652]; furthermore, ABCC2 expression is associated with cisplatin resistance and clinical outcome in other cancers [PMID: 17145840]. Within the VEGF pathway, the top significant SNPs were in the same haplotype block of VEGFR1/FLT1 (rs1324057, rs7324547, r2=1.0): for rs1324057, the aHR for OS was 1.59 (95%CI 1.2-2.1); p=0.001; and the aHR for PFS, 1.48 (95%CI 1.1-1.9); p=0.004. VEGFR1/FLT1 rs7324547 has been associated with esophageal cancer risk [PMID: 21751195], but has not been assessed in lung cancer. Conclusions: SNPS of the VEGFR1 and ABCC2 genes are strongly associated with OS and PFS in this cohort of platinum-treated advanced NSCLC patients. Future studies should assess whether these are predictive or prognostic markers.