[The expression and imprinting status of insulin-like growth factor 2 gene in colorectal cancer].

ABSTRACT

OBJECTIVE: To study the imprinting status and expression level of insulin-like growth factor 2 (IGF2) gene in colorectal cancer and to provide a clue for the mechanism of carcinogenesis of colorectal cancer. METHODS: The expression levels of IGF2 in the paired colorectal cancer and adjacent normal tissue were examined and compared by use of semi-quantitative reverse transcription-polymerase chain reaction. The imprinting status of IGF2 was detected by restriction fragment length polymorphism. The relationships between the expression level of IGF2, its imprinting status, and the carcinogenesis of colorectal cancer were analyzed. RESULTS: IGF2 was overexpressed in 82.4% (28/34) of colorectal cancer tissues which was significantly higher than those of the matched normal tissues (P<0.01, t=3.01). 87.5% (14/16) of colorectal cancer showed loss of imprinting(LOI), while 71.4%(10/14) of normal tissues also displayed LOI of IGF2. CONCLUSION: Overexpression of IGF2 was found to play an important role in carcinogenesis of colorectal cancer. LOI of IGF2 may be a prophase manifestation of colorectal cancer.