Overexpression of DARPP-32 in colorectal adenocarcinoma

Dopamine and cAMP-regulated phosphoprotein (DARPP)-32 is a phosphoprotein that is centrally involved in dopamine signalling pathways. It may play an important role in gastric tumorigenesis. Our aim is to investigate the expression of DARPP-32 protein in colorectal adenocarcinoma. The expression of DARPP-32 was evaluated by immunohistochemical SABC staining and Western blotting. DARPP-32 was specifically localised in colorectal epithelium. The expression of DARPP-32 in colorectal adenocarcinoma tissues 33/42, 78.57% was higher than that in normal colon epithelial tissues (31/60, 51.67%, p < 0.05). There was no significant relationship between the expression of DARPP-32 and the differentiation, metastasis and Dukes' stage of colorectal adenocarcinoma (p > 0.05). Both DARPP-32 and its truncated isoform t-DARPP were overexpressed in colorectal adenocarcinoma (t = 2.306, p = 0.028), while t-DARTP was more frequently detected. These results showed that DARPP-32 may play an important role in the regulation of normal colorectal epithelial biology and carcinogenesis. (C) 2004 Blackwell Publishing Ltd.