0001). Abbreviation: risk groups* = high risk group: patients with high disease stage (stage III, IV) and high VEGF expression score (3-7); low risk group: all other patients. Tumour stage and VEGF expression, Rucaparib chemical structure as one combined variable – the significant mortality predictor by multivariate analysis The full Cox proportional-hazards regression model containing all predictors was statistically significant (P < 0.001), indicating that this model was able to distinguish between survival and non-survival. As shown in Table 6, three predictor variables significantly affected the model, unfavourable histology, high disease stage, and transplantation.

Although we did not demonstrate the role of VEGF as an independent prognostic factor by multivariate analysis, the combination of high tumour stage and high VEGF expression as one complex predictor variable, became the strongest mortality predictor by Cox proportional-hazards regression model (OR = 26.1695, 95% CI = 2.9741 to 230.2670, P = 0.0034;

Table 7). These results showed that prognostic prediction might be improved by taking into account both VEGF CX-5461 clinical trial expression and disease stage. Table 6 Cox proportional-hazards regression model* for NB patients overall survival Covariate P OR** 95% CI***of OR High stage 0.0238 11.3891 1.3949 to 92.9926 VEGF expression score 0.3831 1.1790 0.8159 to 1.7038 Unfavourable histology 0.0073 16.4610 2.1432 to 126.4302 Age older than 18 months 0.1988 3.0418 0.5624 to 16.4532 Without transplantation 0.0295 3.2280 1.1298 to 9.2227 *Overall model

fit χ2 = 42.105 P < 0.0001 Abbreviations: **Odds ratio; *** Confidence interval Table 7 Cox proportional-hazards regression model* including High risk** covariate for NB patients overall survival Covariate P OR*** 95%CI****of OR High risk 0.0034 26.1695 2.9741 to 230.2670 why Without transplantation 0.0111 4.2160 1.3949 to 12.7425 Unfavourable histology 0.0052 20.4384 2.4824 to 168.2770 Age older than 18 months 0.6819   1.4019 0.2809 to 6.9955 *Overall model fit χ2 = 45.904 P < 0.0001 Abbreviations: ** High VEGF expression (score3-7) together with high disease stage (Stage III, IV);***Odds ratio; ****Confidence interval Discussion So far, in some adult solid tumours semi-quantitative VEGF expression has been successfully evaluated by immunohistochemistry, and VEGF has been reported to be an independent prognostic factor [11–15]. We performed similar investigation in the cohort of patients with neuroblastoma which is the most frequent extra cranial solid malignancy in children and has a great mortality rate. In order to evaluate the prognostic significance of VEGF expression in NB patients, and estimate its diagnostic usefulness in a routine clinical practice, we have attempted to establish semi-quantitative VEGF score. As we intended to focus on positivity in viable tumour tissue, the most reliable method was immunohistochemistry.