Interesting markers emerging from retrospective series, prospective trials with a formal statistical hypothesis have never been conducted. To the best of our knowledge, our work represents the first proof of concept sustaining this approach in the field of colorectal oncology. The trial, designed on the basis of our retrospective findings, attests the failure of VEGFA rs833061C/T SNP as a potential predictor of benefit from BV and does not confirm previous results about other candidate SNPs. With regard to VEGFR2 12505758 C/T SNP, whose prognostic rather than predictive impact has been previously suggested [16], we should acknowledge that the significance of the correlation Table 5. VEGFA 833061 SNP allelic variants and response.Table 6. Other candidate VEGFA, VEGFR1, VEGFR2 and EPAS1 SNPs allelic variants and RECIST response.Tumor ResponseN VEGFAAA AG GGCRPRSDPDP* value257 17 (7 ) 127 (50 ) 80 (32 ) 29 (11 ) 144 8 (6 16574785 ) 77 (55 ) 47 (33 ) 9 (6 ) 23 0 (0 ) 15 (65 ) 4 (17 ) 4 (17 ) 0.VEGFACC AC AA 148 4 (3 ) 84 (57 ) 49 (33 ) 10 (7 ) 199 14 (7 ) 97 (50 ) 61 (31 ) 22 (11 ) 0.94 77 7 (9 ) 38 (50 ) 21 (28 ) 10 (13 )VEGFR1AA AG GG 270 12 (5 ) 142 (54 ) 87 (33 ) 24 (9 ) 138 12 (9 ) 68 (50 ) 39 (29 ) 17 (13 ) 0.89 16 1 (6 ) 9 (56 ) 5 (31 ) 1 (6 )VEGFR1AA AC CC 241 11 (5 ) 128 (54 ) 75 (32 ) 23 (10 ) 158 11 (7 ) 80 (51 ) 47 (30 ) 18 (12 ) 0.72 25 3 (13 ) 11 (46 ) 9 (38 ) 1 (4 )VEGFR2TT CT CC 143 9 (6 ) 81 (57 ) 38 (27 ) 13 (9 ) 212 13 (6 ) 103 (50 ) 69 (33 ) 23 (11 ) 0.45 69 3 (4 ) 35 (51 ) 24 (35 ) 6 (9 )VEGFR2TT CT CC 306 22 (7 ) 156 (52 ) 95 (31 ) 29 (10 ) 107 3 (3 ) 55 (53 ) 34 (33 ) 12 (12 ) 0.50 11 0 (0 ) 8 (73 ) 2 (18 ) 1 (9 )VEGFR2Tumor Response CC SD PD 354 22 (6 ) 186 (54 ) 106 (31 ) 33 (10 ) 66 4 3 (4 ) 33 (47 ) 25 (36 ) 9 (13 ) 0.N E studies suggest that over-expression of ODC contributes to transformation by VEGFATT CT CCCRPRP* valueCT{ TT{EPAS1147 4 (3 ) 83 (57 ) 48 (33 ) 61 (32 ) 22 (28 ) 11 (8 ) 21 (11 ) 0.99 10 (13 ) GG AG{ AA{ 332 22 (7 ) 175 (54 ) 96 (29 ) 33 (10 ) 87 5 3 (3 ) 44 (48 ) 35 (38 ) 9 (10 ) 0.18 197 14 (7 ) 96 (50 ) 79 7 (9 ) 39 (50 )*P value was based on Cochran-Mantel-Haenszel test for response and log-rank test for PFS and OS. doi:10.1371/journal.pone.0066774.t*P value was based on Cochran-Mantel-Haenszel test for response and log-rank test for PFS and OS. doi:10.1371/journal.pone.0066774.tPredictors of Benefit from S in NCBIof best hitsratio of best hit / sequences in NCBIrank BevacizumabTable 7. Other candidate VEGFA, VEGFR1, VEGFR2 and EPAS1 SNPs allelic variants and survival outcomes.Progression-Free SurvivalOverall SurvivalN VEGFAAA AG GG 257 144Median PFS, mos (95 CI)HR (95 CI)P* valueMedian OS, mos (95 CI)HR (95 CI)P* value10.4 (9.8, 11.5) 10.5 (9.6, 11.9) 9.6 (8.1, 11.0)1 (Reference) 1.03 (0.80, 1.32) 1.44 (0.87, 2.39) 0.29.1 (23.5, 37.8) 33.0 (23.9, 42.0) 32.1 (16.3, 49.2+)1 (Reference) 0.97 (0.70, 1.35) 1.30 (0.68, 2.50) 0.VEGFACC AC AA 148 199 77 10.2 (9.5, 11.1) 10.7 (9.6, 11.8) 10.3 (9.4, 12.7) 1 (Reference) 0.86 (0.66, 1.11) 0.86 (0.62, 1.19) 0.46 32.6 (24.8, 53.5) 30.9 (23.5, 38.4) 29.2 (21.2, 37.8) 1 (Reference) 1.11 (0.78, 1.57) 1.06 (0.68, 1.65) 0.VEGFR1AA AG GG 270 138 16 10.5 (9.6, 11.6) 10.3 (9.6, 11.3) 9.2 (7.8, 16.6) 1 (Reference) 1.15 (0.90, 1.47) 0.97 (0.51, 1.84) 0.52 31.6 (25.9, 38.0) 28.6 (21.7, 37.8) 60.4+ (20.0, 60.4+) 1 (Reference) 1.15 (0.83, 1.58) 0.82 (0.35, 1.90) 0.VEGFR1AA AC CC 241 158 25 11.0 (10.0, 12.5) 10.1 (9.5, 10.8) 10.5 (7.8, 14.0) 1 (Reference) 1.25 (0.98, 1.58) 1.15 (0.68, 1.96) 0.19 32.6 (26.3, 44.1) 28.6 (23.3, 34.6) 37.8 (20.0, 60.4+) 1 (Reference) 1.17 (0.85, 1.60) 0.99 (0.51, 1.92) 0.VEGFR2TT CT CC 14.Interesting markers emerging from retrospective series, prospective trials with a formal statistical hypothesis have never been conducted. To the best of our knowledge, our work represents the first proof of concept sustaining this approach in the field of colorectal oncology. The trial, designed on the basis of our retrospective findings, attests the failure of VEGFA rs833061C/T SNP as a potential predictor of benefit from BV and does not confirm previous results about other candidate SNPs. With regard to VEGFR2 12505758 C/T SNP, whose prognostic rather than predictive impact has been previously suggested [16], we should acknowledge that the significance of the correlation Table 5. VEGFA 833061 SNP allelic variants and response.Table 6. Other candidate VEGFA, VEGFR1, VEGFR2 and EPAS1 SNPs allelic variants and RECIST response.Tumor ResponseN VEGFAAA AG GGCRPRSDPDP* value257 17 (7 ) 127 (50 ) 80 (32 ) 29 (11 ) 144 8 (6 16574785 ) 77 (55 ) 47 (33 ) 9 (6 ) 23 0 (0 ) 15 (65 ) 4 (17 ) 4 (17 ) 0.VEGFACC AC AA 148 4 (3 ) 84 (57 ) 49 (33 ) 10 (7 ) 199 14 (7 ) 97 (50 ) 61 (31 ) 22 (11 ) 0.94 77 7 (9 ) 38 (50 ) 21 (28 ) 10 (13 )VEGFR1AA AG GG 270 12 (5 ) 142 (54 ) 87 (33 ) 24 (9 ) 138 12 (9 ) 68 (50 ) 39 (29 ) 17 (13 ) 0.89 16 1 (6 ) 9 (56 ) 5 (31 ) 1 (6 )VEGFR1AA AC CC 241 11 (5 ) 128 (54 ) 75 (32 ) 23 (10 ) 158 11 (7 ) 80 (51 ) 47 (30 ) 18 (12 ) 0.72 25 3 (13 ) 11 (46 ) 9 (38 ) 1 (4 )VEGFR2TT CT CC 143 9 (6 ) 81 (57 ) 38 (27 ) 13 (9 ) 212 13 (6 ) 103 (50 ) 69 (33 ) 23 (11 ) 0.45 69 3 (4 ) 35 (51 ) 24 (35 ) 6 (9 )VEGFR2TT CT CC 306 22 (7 ) 156 (52 ) 95 (31 ) 29 (10 ) 107 3 (3 ) 55 (53 ) 34 (33 ) 12 (12 ) 0.50 11 0 (0 ) 8 (73 ) 2 (18 ) 1 (9 )VEGFR2Tumor Response CC SD PD 354 22 (6 ) 186 (54 ) 106 (31 ) 33 (10 ) 66 4 3 (4 ) 33 (47 ) 25 (36 ) 9 (13 ) 0.N VEGFATT CT CCCRPRP* valueCT{ TT{EPAS1147 4 (3 ) 83 (57 ) 48 (33 ) 61 (32 ) 22 (28 ) 11 (8 ) 21 (11 ) 0.99 10 (13 ) GG AG{ AA{ 332 22 (7 ) 175 (54 ) 96 (29 ) 33 (10 ) 87 5 3 (3 ) 44 (48 ) 35 (38 ) 9 (10 ) 0.18 197 14 (7 ) 96 (50 ) 79 7 (9 ) 39 (50 )*P value was based on Cochran-Mantel-Haenszel test for response and log-rank test for PFS and OS. doi:10.1371/journal.pone.0066774.t*P value was based on Cochran-Mantel-Haenszel test for response and log-rank test for PFS and OS. doi:10.1371/journal.pone.0066774.tPredictors of Benefit from BevacizumabTable 7. Other candidate VEGFA, VEGFR1, VEGFR2 and EPAS1 SNPs allelic variants and survival outcomes.Progression-Free SurvivalOverall SurvivalN VEGFAAA AG GG 257 144Median PFS, mos (95 CI)HR (95 CI)P* valueMedian OS, mos (95 CI)HR (95 CI)P* value10.4 (9.8, 11.5) 10.5 (9.6, 11.9) 9.6 (8.1, 11.0)1 (Reference) 1.03 (0.80, 1.32) 1.44 (0.87, 2.39) 0.29.1 (23.5, 37.8) 33.0 (23.9, 42.0) 32.1 (16.3, 49.2+)1 (Reference) 0.97 (0.70, 1.35) 1.30 (0.68, 2.50) 0.VEGFACC AC AA 148 199 77 10.2 (9.5, 11.1) 10.7 (9.6, 11.8) 10.3 (9.4, 12.7) 1 (Reference) 0.86 (0.66, 1.11) 0.86 (0.62, 1.19) 0.46 32.6 (24.8, 53.5) 30.9 (23.5, 38.4) 29.2 (21.2, 37.8) 1 (Reference) 1.11 (0.78, 1.57) 1.06 (0.68, 1.65) 0.VEGFR1AA AG GG 270 138 16 10.5 (9.6, 11.6) 10.3 (9.6, 11.3) 9.2 (7.8, 16.6) 1 (Reference) 1.15 (0.90, 1.47) 0.97 (0.51, 1.84) 0.52 31.6 (25.9, 38.0) 28.6 (21.7, 37.8) 60.4+ (20.0, 60.4+) 1 (Reference) 1.15 (0.83, 1.58) 0.82 (0.35, 1.90) 0.VEGFR1AA AC CC 241 158 25 11.0 (10.0, 12.5) 10.1 (9.5, 10.8) 10.5 (7.8, 14.0) 1 (Reference) 1.25 (0.98, 1.58) 1.15 (0.68, 1.96) 0.19 32.6 (26.3, 44.1) 28.6 (23.3, 34.6) 37.8 (20.0, 60.4+) 1 (Reference) 1.17 (0.85, 1.60) 0.99 (0.51, 1.92) 0.VEGFR2TT CT CC 14.