Expression profile of the REG gene family in colorectal carcinoma

Regenerating (REG) gene family belongs to the calcium-dependent lectin gene superfamily and encodes small multifunctional secretory proteins, which might be involved in cell proliferation, differentiation, and carcinogenesis. To clarify REG expression profile in colorectal carcinoma (CRC), the authors examined the expression of REG Iα, Iβ, III, HIP/PAP, and REG IV by immunohistochemistry on tissue microarray. The expression of REG Iα, III, and HIP/PAP was more frequently observed in the CRCs than adjacent non-neoplastic mucosa (p < 0.001), whereas it was the converse for REG Iβ and IV (p < 0.001). The expression of REG Iα, Iβ, III, and HIP/PAP was negatively correlated with the depth of invasion of CRCs (p < 0.05). The REG Iβ and HIP/PAP were less expressed in CRCs with than without venous invasion (p < 0.05). The positive rates of REG Iα and HIP/PAP were significantly higher in CRCs without than with lymph node metastasis (p < 0.05). Mucinous carcinoma more frequently expressed REG IV protein than well- and moderately differentiated ones (p < 0.05). There was a positive relationship between REG Iα, Iβ, III, and HIP/PAP expression (p < 0.05). Survival analysis indicated the REG Iβ or HIP/PAP expression was positively linked to favorable prognosis of carcinoma patients (p < 0.05). This study indicated that aberrant REG expression might be closely linked to the pathogenesis, invasion, or lymph node metastasis of CRCs. REG Iβ and HIP/ PAP could be considered reliable markers of favorable prognosis of CRC patients.