Guan et al. BMC Cancer 2010, 10:431 http://www.biomedcentral.com/1471-2407/10/431 Page 5 of 9 Figure 2 PCR-based restriction analysis of the VEGF SNPs shown on agarose electrophoresis. variant genotypes (n = 91) were associated significantly with improved OS (adjusted HR = 0.58; 95% CI = 0.37- 0.92, P = 0.022) (Figure 3A), compared with the VEGF -460 TT genotype (n = 33). For the other two VEGF SNPs -634 G > C and +936 C > T, we repeated the ana- lyses but did not find any significant associations under either the additive model or dominant model (Table 2 and Figure 3B and 3C). To determine if the influence of VEGF SNPs was sub- stantially affected by tumor stage, we further made stra- tified analyses by separating the patients into two subgroups, stages IIIa and IIIb. We found that none of the three SNPs showed significant influence on OS, except for the CT genotype of VEGF -460 T > C SNP, which was marginally associated with increased OS in NSCLC patients of stage IIIb (adjusted HR = 0.56; 95% CI, 0.30-1.05, P = 0.071 and other data not shown). VEGF haplotypes and NSCLC survival We further explored the haplotypes to evaluate the combined effect of the three polymorphisms on NSCLC survivals. There were five haplotypes with frequencies > 5% among all cases, and other less common haplotypes (frequencies < 5%) were combined into one group. The five most common haplotypes in the patients were -460C/-634G/+936C (C-G-C), T-C-C, T-G-C, T-C-T, and C-C-C with the respective frequencies of 38.8%, 23.8%, 17.7%, 8.8% and 5.4%, which were similar to those reported in the other Caucasian populations [15]. However, we did not find a significant impact on OS from the other haplotypes, compared to the most com- mon C-G-C haplotype (data not shown). Discussion Several studies have reported the association between VEGF polymorphisms and progress and survival of dif- ferent cancers [16-19], but no study has investigated the association between the VEGF polymorphisms and LA-NSCLC patients’ survival to date. To reduce Table 2 Association between VEGF genotypes and overall survival Genotypes Case No. Deaths No. (%)* MST (95% CI, month) Crude HR (95% CI) Adjusted HR (95% CI) VEGF -460T > C (rs833061) TT 33 CT 67 CC 24 CT+CC 91 VEGF -634G > C (rs2010963) GG 57 CG 41 CC 26 CG+CC 67 VEGF +936C > T (rs3025039) CC 92 CT 30 TT 2 CT+TT 32 28 (84.9) 47 (70.2) 17 (70.8) 64 (70.3) 40 (70.2) 34 (82.9) 18 (69.2) 52 (76.1) 68 (73.9) 22 (73.3) 2 (100) 24 (75.0) 16.0 (11.0-25.0) 21.0 (17.0-32.0) 27.0 (10.0-36.0) 21.0 (17.0-31.0) 23.0 (16.0-36.0) 17.0 (13.0-25.0) 12.0 (9.0-29.0) 17.0 (12.0-24.0) 21.0 (16.0-29.0) 17.0 (11.0-29.0) 14.5 (9.0-20.0) 17.0 (11.0-28.0) 1.00 0.60 (0.37-0.95) 0.75 (0.41-1.37) 0.63 (0.40-0.99) 1.00 1.20 (0.76-1.90) 1.25 (0.71-2.18) 1.22 (0.80-1.84) 1.00 1.08 (0.67-1.75) 2.14 (0.52-8.80) 1.13 (0.71-1.80) P† 0.031 0.347 0.043 0.440 0.436 0.356 0.742 0.291 0.606 1.00 0.56 (0.34-0.90) 0.67 (0.36-1.26) 0.58 (0.37-0.92) 1.00 1.17 (0.74-1.88) 1.28 (0.72-2.28) 1.21 (0.79-1.84) 1.00 1.00 (0.60-1.66) 1.95 (0.46-8.29) 1.05 (0.65-1.71) P‡ 0.018 0.212 0.022 0.502 0.399 0.379 0.992 0.367 0.839 Abbreviation: MST, median survival time. * Percentage of deaths in each stratum † P values were calculated using the log-rank test in the univariate analysis. ‡ P values were obtained from the Cox hazards model with adjustment for age, sex, smoking status, tumor histology, KPS score, tumor stage, application of chemotherapy and radiotherapy dose.