Interleukin-6 (IL-6) is a multifunctional cytokine produced by macrophages, T cells, B cells, endothelial cells and tumour cells. Interleukin-6 is able to promote tumour growth by upregulating anti-apoptotic and angiogenic proteins in tumour cells. In murine models it has been demonstrated that antibodies against IL-6 diminish tumour growth. Several reports have highlighted the prognostic importance of IL-6 in e.g., prostate and colon cancer. We addressed prospectively the prognostic significance of serum IL-6 (sIL-6), measured at diagnosis of metastasis, in 96 unselected and consecutive patients with progressive metastatic breast cancer before the initiation of systemic therapy. The median sIL-6 value for the breast cancer population was 6.6 ؎ 2.1 pg/ml. Patients with 2 or more metastatic sites had higher sIL-6 values compared to those with only 1 metastatic site (respectively 8.15 ؎ 1.7 pg/ml and 3.06 ؎ 6.6 pg/ml; p < 0.001). Patients with liver metastasis (8.3 ؎ 2.4 pg/ml), with pleural effusions (10.65 ؎ 9.9 pg/ml) and with dominant visceral disease (8.15 ؎ 3.3 pg/ml) had significantly higher values compared to those without liver metastases (4.5 ؎ 3.4 pg/ml; p ‫؍‬ 0.001), without pleural effusions (5.45 ؎ 1.5 pg/ml; p ‫؍‬ 0.0077) and with dominant bone disease (4.5 ؎ 1.4 pg/ml; p ‫؍‬ 0.007) respectively. No correlation between sIL-6 and age, menopausal status, performance status, tumour grade, bodymass index, histology and hormone receptor status was found. Multivariate analysis showed that high levels of serum IL-6 have independent prognostic value. We conclude that circulating IL-6 is associated with worse survival in patients with metastatic breast cancer and is correlated with the extent of disease.

Plasma levels of D-dimer are elevated in cancer patients. Activation of the extrinsic coagulation system and the fibrinolytic cascade within a tumour is thought to be related with growth, invasion and metastasis. We have investigated the relationship between these markers of fibrin metabolism, standard clinicopathological variables and serum levels of angiogenic cytokines in three cohorts: group A (n=30) consisted of 30 healthy female volunteers, group B (n=23) of consecutive patients with operable breast cancer and group C (n=84) of patients with untreated or progressive metastatic breast cancer. Plasma Ddimers, fibrinogen, IL-6, vascular endothelial growth factor and calculated vascular endothelial growth factor load in platelets are clearly increased in patients with breast cancer. D-dimers were increased in nearly 89% of patients with progressive metastatic disease. The level of D-dimers was positively correlated with tumour load (P50.0001), number of metastatic sites (P=0.002), progression kinetics (P50.0001) and the cytokines related to angiogenesis: serum vascular endothelial growth factor (P=0.0016, Spearman correlation=0.285), calculated vascular endothelial growth factor load in platelets (P50.0001, Spearman correlation=0.37) and serum interleukin-6 (P50.0001, Spearman correlation=0.59). Similarly increased D-dimer levels were positively correlated with increased fibrinogen levels (P50.0001, Spearman correlation=0.38). The association between markers of fibrin degradation in patients with progressive breast cancer suggests that the D-dimer level is a clinically important marker for progression and points towards a relation between haemostasis and tumour progression. A role of interleukin-6, by influencing both angiogenesis and haemostasis, is suggested by these observations.

SummaryWe have compared the platelet number and the serum concentration of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and interleukin-6 (IL-6) in 80 blood samples of 50 patients with advanced cancer. We have also measured the mitogenic effect of patient sera on endothelial cells in vitro in order to estimate the biological activity of serum VEGF. Serum VEGF concentration correlated with platelet number (r = 0.61; P < 10 -4 ). Serum IL-6 levels correlated with platelet count (r = 0.36; P < 10 -3 ), with serum VEGF levels (r = 0.55; P < 10 -4 ) and with the calculated load of VEGF per platelet (r = 0.4; P = 3 × 10 -4 ). Patients with thrombocytosis had a median VEGF serum concentration which was 3.2 times higher (P < 10 -4 ) and a median IL-6 serum level which was 5.8 times higher (P = 0.03) than in other patients. Serum bFGF did not show an association with any of the other parameters. Patient sera with high VEGF and bFGF content stimulated endothelial cell proliferation significantly more than other sera (P = 4 × 10 -3 ). These results support the role of platelets in the storage of biologically active VEGF. Platelets seem to prevent circulating VEGF from inducing the development of new blood vessels except at sites where coagulation takes place. IL-6, besides its thrombopoietic effect, also seems to affect the amount of VEGF stored in the platelets. This is in accordance with the indirect angiogenic action of IL-6 reported previously. The interaction of IL-6 with the angiogenic pathways in cancer might explain the stimulation of tumour growth occasionally observed during IL-6 administration. It also conforms to the worse outcome associated with high IL-6 levels and with thrombocytosis in several tumour types and benign angiogenic diseases.

BACKGROUND: The detection, enumeration and isolation of circulating tumour cells (CTCs) have considerable potential to influence the clinical management of patients with breast cancer. There is, however, substantial variability in the rates of positive samples using existing detection techniques. The lack of standardisation of technology hampers the implementation of CTC measurement in clinical routine practice. METHODS: This study was designed to directly compare three techniques for detecting CTCs in blood samples taken from 76 patients with metastatic breast cancer (MBC) and from 20 healthy controls: the CellSearch CTC System, the AdnaTest Breast Cancer Select/ Detect and a previously developed real-time qRT-PCR assay for the detection of CK-19 and mammaglobin transcripts. RESULTS: As a result, 36% of patients with MBC were positive by the CellSearch System, 22% by the AdnaTest, 26% using RT -PCR for CK-19 and 54% using RT -PCR for mammaglobin. Samples were significantly more likely to be positive for at least one mRNA marker using RT -PCR than using the CellSearch System (P ¼ 0.001) or the AdnaTest (Po0.001). CONCLUSION: We observed a substantial variation in the detection rates of CTCs in blood from breast cancer patients using three different techniques. A higher rate of positive samples was observed using a combined qRT-PCR approach for CK-19 and mammaglobin, which suggests that this is currently the most sensitive technique for detecting CTCs.