Serum vascular endothelial growth factor load and interleukin-6 in cancer patients – reply

) from 25 healthy volunteers, 30 previously untreated patients with operable breast cancer and 70 patients with advanced breast cancer. The healthy volunteers had a VEGF load of 0.41 pg 10 ‐6 platelets, which gradually increased to 1.00 pg 10 ‐6 platelets for the non-metastatic group to 1.58 pg 10 ‐6 platelets for the advanced group (Kruskal‐Wallis test, P < 0.0001). We have previously suggested that interleukin-6 (IL-6) might be particularly important in tumour-related angiogenesis (Salgado et al, 1999). Preliminary data derived from the same three subsets of patients confirm these data, showing a significant correlation between circulating levels of IL-6 and the VEGF PLT in the group with advanced breast cancer (Spearman rank test, P < 0.002). A significant difference was also observed between mean IL-6 levels in the control vs locoregional disease group (0.5 pg ml ‐1 vs 1.4 pg ml ‐1 respectively, Mann‐Whitney U-test, P = 0.041) and between these and the advanced group (1.4 pg ml ‐1 vs 12.4 pg ml ‐1 respectively, Mann‐Whitney U-test, P < 0.0001). In a second study we measured serum IL-6 levels in the effluent mesenteric vein in seven patients suffering from an operable colorectal carcinoma and compared these values with those obtained from an arterial (art.) and peripheral venous (pv.) blood sample. Arterial and peripheral venous IL-6 did not reach the detection limit of the assay (3.1 pg ml ‐1 ) in 75% and 63% of the patients respectively (means of 2.2 pg ml ‐1 and 2.5 pg ml ‐1 respec