Expression of fibulin-1 predicted good prognosis in patients with colorectal cancer.

Fibulin-1, a multi-functional extracellular matrix protein, has been demonstrated to be involved in many kinds of cancer, while its function in colorectal cancer (CRC) is unclear. So here we investigated the expression and function of fibulin-1 in CRC. The expression of fibulin-1 mRNA variants named A, B, C and D in human colorectal cancer cells and colorectal cancer specimens were determined by RT-PCR. Fibulin-1 protein expression in colorectal cancer and normal colorectal mucosa tissue was evaluated by western blot, and was further validated by immunohistochemistry and enzyme-linked immunosorbent assay at serum level. The correlations between fibulin-1 expression and the clinicopathological features of colorectal cancers were evaluated by Chi-square test and Fisher's exact tests. The survival rates were calculated by the Kaplan-Meier method. Among fibulin-1 A-D variants, fibulin-1D is the predominant form expressed in colorectal cancer cell lines and colorectal cancer tissue, whereas only trace amounts of fibulin-1A-C were detectable. Fibulin-1 expressed higher in the CRC tissues and serum compared to normal control. So in the process of tumorigenesis of CRC, fibulin-1 is upregulated, however, high fibulin-1 expression showed longer survival time in colorectal cancer patients, especially in the patients with stage I/II. Low fibulin-1 expression was significantly associated with lymph node involvement, distant metastasis and Dukes' C and D stage (P < 0.05 for each). Fibulin-1 protein expression may be useful as a diagnosis and prognosis marker for colorectal cancer.