Increased TGF-beta1 protein expression in patients with advanced colorectal cancer

Introduction: There is evidence that TGF-beta 1 plays a role as a tumor suppressor in early disease and has pro-oncogenic effects in advanced tumor stage. The aim of the study was to correlate TGF-beta 1 in plasma and tissue to clinical and pathological parameters in patients with various stages of disease progression. Methods: One hundred sixty-nine patients who underwent surgery for a colorectal carcinoma were prospectively included. Blood samples, tumor free mucosa and tumor biopsies were assayed. Results: TGF-beta 1 protein expression in tumors increased with increasing T-stage regardless of whether patients with metastatic disease were included or not (P = 0.0006). Patients with metastatic disease showed elevated TGF-beta 1 protein expression in both tumor tissue (P = 0.004) and plasma (P = 0.001) compared to those without metastatic disease. TGF-beta 1 protein expression was higher in the colon compared with the rectum in both tumor tissue and tumor-free bowel (P = 0.03), regardless of whether patients with metastatic disease were included or not. This difference was mainly attributable to a higher TGF-beta 1 protein expression in non-metastatic patients with lymph node positivity (P = 0.005). Conclusions: Higher TGF-beta 1 protein expression is associated with increasing T-stage and metastatic disease, indicating that TGF-beta 1 is of importance in tumor progression. The localization of the tumor seems to influence the TGF-beta 1 protein expression in patients with tumor cell-positive lymph nodes.