Serum erythropoietin and angiogenetic factors in human colorectal cancer

Erythropoietin, VEGF, VE-cadherin are involved in angiogenesis. Besides that erythropoietin stimulates erythropoiesis and increases haemoglobin and hematocrit levels as well. Moreover, erythropoietin could directly stimulate colorectal cancer cell growth due to the presence of both erythropoietin receptor and erythropoietin production in malignant cells of this neoplasm. Therefore we aimed at measurement and comparison of serum erythropoietin with VEGF, VE-cadherin levels, blood haemoglobin and hematocrit in colorectal cancer patients of different clinicopathological profiles.

We applied ELISA kits to evaluate preoperative serum levels of endogenous erythropoietin, VEGF and VE-cadherin in samples from 92 colorectal cancer patients and control group of 16 healthy volunteers.

Endogenous erythropoietin was significantly elevated in preoperative sera in colorectal cancer patients (p = 0.013) compared with healthy volunteers, however, erythropoietin levels were not significantly higher with the advancement of colorectal cancer. There were significantly higher levels of erythropoietin in the group of anaemic men in comparison to men with normal haemoglobin levels (p < 0.0001). VEGF and VE-cadherin did not correlate with erythropoietin. Erythropoietin levels negatively correlated with haemoglobin and hematocrit levels in all cancer patients; particularly in node positive cancers (N+), moderately differentiated tumours (G2) and deeply invading neoplasms (pT3+pT4).

Erythropoietin levels increase in colorectal cancer but circulating erythropoietin does not associate with progression of the disease. Thus, the use of recombinant erythropoietin seems to be safe. Our results suggest that negative feedback regulation persists between haemoglobin and erythropoietin in colorectal cancer. Production of erythropoietin remains therefore anaemia-associated, hypoxia-dependent and doesn't seem to be autonomic despite abundant expression of erythropoietin by colorectal cancers.