Transforming growth factor‐β1 (TGF‐β1) acts as a potent inhibitor of cell growth and tumor progression but loss of this negative regulation can contribute to tumor development. Some studies have reported an association between disease progression and TGF‐β1 expression in patients with colorectal carcinoma, but their results were not always consistent.

Serum levels of TGF‐β1 were measured using an enzyme‐linked immunoadsorbent assay in 121 consecutive patients with colorectal carcinoma and compared with TGF‐β1 serum levels in 31 healthy volunteers. Serum levels of TGF‐β1 also were measured in 50 patients who underwent curative surgical resection (part of the 121 preoperative patients) to compare their levels with preoperative serum levels of TGF‐β1.

Serum levels of TGF‐β1 in patients with colorectal carcinoma (45 ± 15 ng/mL) (mean ± the standard deviation) were significantly higher than those in the healthy control group (32 ± 4 ng/mL) (P = 0.001). Serum levels of TGF‐β1 increased with increasing tumor stage (P < 0.01). Serum levels of TGF‐β1 were correlated significantly with depth of tumor invasion, lymph node metastasis, distant metastasis, and serum levels of carcinoembryonic antigen (CEA). Serum levels of TGF‐β1 tended to increase with increasing CEA (correlation coefficient = 0.21; P < 0.05). The mean serum level of TGF‐β1 in patients with colorectal carcinoma before surgery (45 ± 14 ng/mL) (n = 50) significantly decreased to 34 ± 7 ng/mL, which was within the normal range (32 ± 4 ng/mL), after curative surgical resection of the tumor (P = 0.0000). Serum levels of TGF‐β1 after tumor resection decreased more significantly in patients with higher preoperative levels of TGF‐β1 (from 53 ± 12 ng/mL to 36 ± 6 ng/mL) (n = 30).

The results of the current study suggest that serum levels of TGF‐β1 in colorectal carcinoma patients may be associated with disease progression and may be used as a biomarker in the management of colorectal carcinoma patients. The authors believe further studies with a large number of patients for a longer follow‐up period are necessary to conclude whether serum levels of TGF‐β1 carry significant clinical relevance. [See editorial on pages 517–9, this issue]. Cancer 1999;85:554–61. © 1999 American Cancer Society.