Transforming growth factor-beta1 in invasion and metastasis in colorectal cancer

To investigate the role of TGFbeta1 in invasion and metastasis in colorectal cancer by analysing TGFbeta1 correlated with depth of tumor invasion, stage and metastasis.

Serum TGFbeta1 levels were determined in 50 patients with colorectal cancer and 30 healthy volunteers using a TGFbeta1 enzyme-linked immunosorbent assay. TGFbeta1 expression in primary and lymph node metastatic lesions were detected in 98 cases of colorectal cancer by immunohistochemical staining and in situ hybridization.

Serum levels of TGFbeta1 in patients with colorectal cancer(40+/-18 microg.L(-1)) were significantly higher than those in the healthy control group(19+/-8 microg.L(-1)), P<0.05. Elevated levels of serum TGFbeta1 were found in 60 % of patients with colorectal cancer when the mean +2 s was used as the upper limit of the normal range (35.1 microg.L(-1)). Increases in serum TGFbeta1 levels were significantly associated with Duke's stage (P<0.05), but there was no significant difference between Duke's stage B patients and Duke's stage C patients. In the cytoplasm of cancer cells, TGFbeta1 was immunostained in 37.8 % (37/98) of colorectal cancer, and this expression was confirmed by in situ hybridization. Among 35 cases of colorectal cancer with lymph node metastatic lesions, TGFbeta1 positive staining was found in 18 (51.4 %) cases of primary tumor, and 25 (71.4 %) cases with lymph node metastatic lesions, respectively. Of 17 cases w ith no staining in the primary lesion, 7 (41.2%) casesshowed TGFbeta1 staining in the metastatic lesion. Serum TGFbeta1 levels and TGFbeta1 expression in colorectal cancer tissues were correlated significantly with depth of tumor invasion, stage and metastasis. Patients in stage C-D,T3-T4 and with metastasis had significantly higher TGFbeta1 levels than patients in stage A-B,T1-T2 and without metastasis (P<0.05).

These results suggest that transforming growth factor-beta1 is closely related to the invasion and metastasis of colorectal cancer. It increased the invasive and metastatic potential of tumor by altering a tumor microenvironment. TGFbeta1 may be used as a possible biomarker.