OBJECTIVETo investigate the expression and amplification of steroid receptor coactivator- 3(SRC- 3) gene in colorectal carcinoma (CRC) and its clinicopathological significance.

METHODSImmunohistochemistry and fluorescence in situ hybridization (FISH) were used to detect the expression and amplification of SRC- 3 gene in CRC, and its association with patient's clinical pathological features was analyzed.

RESULTSA total of 60 patients with CRC were studied. SAR- 3 proteins were overexpressed in 23 cases (38% ). There was a significant association between SAR- 3 overexpression and neoplasm staging (P< 0.01). SRC- 3 protein was overexpressed in 62% of patients with Dukes C or D stage, whereas SRC- 3 protein was normally expressed in 74% of patients with Dukes A or B stage. As for FISH study, 47 cases were informative. High- level amplification of SRC- 3 gene was detected in 6 cases(13% ) and all showed overexpression of SRC- 3 protein. Low- level amplification of SRC- 3 was observed in 9 cases (19% ). Overexpression of SRC- 3 was detected in 6 cases. The remaining 9 of 32 patients(28% ) without amplification of SRC- 3 gene were observed with overexpression of SRC- 3 protein. In addition, 91% patients with CRC were found overexpression of SRC- 3 as well as overexpression of P53.

CONCLUSIONThe abnormal expression of SRC- 3 gene might impact on the function of P53 and development of CRC. There might exist some unknown mechanisms other than gene amplification of SRC- 3 to regulate its encoded protein expression in CRC.