OBJECTIVETo investigate the expression of metastasis-associated colon cancer 1 (MACC1) protein in colorectal cancer and its clinical significance.

METHODSImmunohistochemistry method was used to determine the expression of MACC1 protein in colorectal cancer and normal colorectal mucosal tissues (>5 cm distance to cancer tissue). Statistic analysis was performed to investigate the association between clinicopathologic features and MACC1 expression.

RESULTSThe positive rate of MACC1 protein in colorectal cancer tissues was significantly higher than that in normal tissues [75%(72/96) vs. 14.6%(14/96), P<0.01, χ(2)=68.43]. Expression of MACC1 protein was associated with TNM staging (P<0.01, χ(2)=16.82) and distant metastasis (P<0.01, χ(2)=10.53), but not with age, gender, tumor size, differentiation degree, invasion depth, and lymph node metastasis(all P>0.05). Positive rate of MACC1 expression increased with the advanced TNM staging. When distant metastasis occurred, high expression of MACC1 protein in cancer tissues was found. During median 13(4 to 21) months of follow-up, 7 patients died, including 6(8.3%, 6/72) with high expression and 1(4.2%, 1/24) with low expression. Distant metastasis occurred in 9 patients, including 7 with high expression and 2 with low expression. Two patients had local relapse, whose MACC1 expressions were both high.

CONCLUSIONMACC1 protein is highly expressed in colorectal cancer tissues, which may be associated with the invasion and metastasis of colorectal cancer.