Background: Nitric oxide (NO) is a free radical that is involved in carcinogenesis. Endothelial NO, synthesized from L-arginine by endothelial NO synthase (eNOS), inhibits apoptosis and promotes angiogenesis, tumor cell proliferation and metastasis. The aim of this study was to evaluate the influence of polymorphisms in the eNOS gene on prognosis of patients with advanced stage non-small-cell lung cancer (NSCLC).
Methods: Unresectable, chemotherapy naïve stage III or IV NSCLC patients who were treated with standard platinum-containing doublet regimens were analyzed. All individuals were genotyped for the single-nucleotide polymorphism G894T in exon 7 of the eNOS gene and for a variable number of tandem repeats (VNTR) polymorphism in intron 4 that results in a rare smaller allele (a) and a common larger allele (b), to investigate the association between these polymorphisms and clinical outcomes. The primary endpoint was correlation with overall survival.
Results: From October 2004 to December 2007, 108 patients (male/female, 66/42; Stage IIIA/IIIB/IV, 6/30/72) aged 29-77 years (median 63) with good performance status were consecutively enrolled in this study. Using Kaplan-Meier estimates, we showed that 5-year overall survival was significantly increased in patients carrying the VNTR a-allele compared with VNTR b/b patients (P = 0.015). In multivariate Cox proportional hazard analysis, the VNTR polymorphism was an independent prognostic factor for survival.
Conclusions: The results support the role of the VNTR polymorphism in intron 4 as a marker for survival in patients with advanced stage NSCLC who are candidates for standard chemotherapy.