AIM: There is strong evidence that interleukin-11 (IL-11) is involved in the regulation of tumor progression, cellular growth and differentiation. Recently, interleukin-11 receptor (IL-11R) has been detected on some cancer cells. In this study, we investigated the expression of IL-11 and IL-11R in colorectal adenocarcinoma.

METHODS: To elucidate the involvement of IL-11 and IL-11Rα in human intestinal adenocarcinomas, we examined 115 cases of surgically resected human colonic adenocarcinoma and 11 cases of adenoma by immunohistochemistry and Western blotting.

RESULTS: Among 115 cases of adenocarcinoma, 100 cases (87.0%) showed positive staining in the cytoplasm of carcinoma cells for the IL-11, and 87 cases (75.6%) were positive for the IL-11Rα. Six cases (54.5%) and four cases (36.4%) of 11 adenomas were positive for IL-11 and IL-11Rα, respectively. The expression of IL-11Rα correlated with the histological differentiation (P= 0.033503), the depth of tumor invasion (P= 0.006395), Dukes’ classification (P= 0.015648) and lymphatic invasion (P= 0.003865). However, the expression of IL-11Rα was not correlated with the venous invasion and the presence of lymph node metastasis. The expression of IL-11 was not correlated with any clinicopathological factors. In Western blot analysis, two human colorectal carcinoma cell lines and four tissues of surgically resected human carcinoma expressed both IL-11 and IL-11Rα proteins.

CONCLUSION: IL-11 and IL-11Rα are highly expressed in human colorectal adenocarcinoma and the IL-11Rα expression is correlated with clinicopathological factors. These findings suggest that the expression of IL-11Rα is an important factor for the invasion of human colorectal adenocarcinoma.