Abstract

BACKGROUND
Insulin-like growth factor binding protein 3 (IGFBP3), a member of six proteins with a high affinity for insulin-like growth factors (IGFs), seems to modulate the effects of IGFs on cells and to regulate cell proliferation through the IGF-independent pathway. We assessed the role of IGFBP3 in the colorectal carcinoma detected by cDNA microarray.
METHODS
To identify molecular alterations in the colorectal carcinoma, we analyzed gene expression profiles of the colorectal adenocarcinoma by means of a cDNA microarray representing 7,500 genes. Of the differentially expressed genes, the author assessed the insulin-like growth factor binding protein 3 (IGFBP3) gene at the protein level using immunohistochemistry.
RESULTS
The expressions of 21 and 16 genes were noted to have more than fivefold increases or decreases in the colonic adenocarcinoma tissue compared with the noncancerous colonic mucosal tissue. The differentially expressed genes include those associated with cell proliferation/apoptosis, signal transduction/transcription, metabolizing enzymes, cytoskeleton, angiogenesis, ion channel, extracellular matrix and others. Of the total 68 cases of colorectal adenocarcinomas observed, 34 cases (50%) showed positive immunohistochemical stainings for IGFBP3.
CONCLUSIONS
In this study, it is suggested that IGFBP3 plays a role in colorectal carcinogenesis. And combining an immunohistochemistry with a cDNA microarray can facillitate the rapid characterization of a candidate novel molecular target.