Transgelin Protein Expression in Colorectal Cancer: A Clinicopathological Study.

Abstract

Transgelin is an actin-binding protein expressed in smooth muscle cells, cancer cells and fibroblasts. While Transgelin has previously been reported to be a tumor suppressor, recent studies have shown that Transgelin is involved in carcinogenesis, with its mRNA expression shown to be associated with poor prognosis in colorectal cancer. To date, however, very few clinicopathological studies have been conducted on Transgelin expression in colorectal cancer tissue. The aim of this study was therefore to elucidate the clinicopathological role of Transgelin expression in colorectal cancer and stromal cells. Ninety-six patients undergoing curative surgery for colorectal cancer between February and December 2012 were enrolled in this study, and immunostaining was performed to examine Transgelin expression in stromal and cancer cells from these patients. Fluorescent double immunostaining was also performed to investigate Transgelin expression in α-SMA-positive, cancer-associated fibroblasts. Transgelin expression was predominately observed in cancer stroma, rather than in cancer cells or normal epithelial cells. While Transgelin expression was shown to be limited in pericryptal fibroblasts, it was shown to be extremely enhanced in stromal fibroblasts. Transgelin expression in cancer stroma was significantly associated with T stage (P < 0.01) and relapse-free survival, while that in cancer cells was not associated with any of the clinicopathological features examined. Again, while α-SMA and Transgelin were shown to be co-expressed in cancer-associated fibroblasts, Transgelin was shown to be predominantly expressed in cancer-associated fibroblasts rather than in cancer cells. Thus, Transgelin may represent a novel marker for cancer-associated fibroblasts.