Downregulated inhibitor of growth 3 (ING3) expression during colorectal carcinogenesis.

Background & objectives: ING3 (inhibitor of growth protein 3) overexpression decreased S-phase cell population and colony-forming efficiency, and induced apoptosis at a p53-mediated manner. The aim of this study was to investigate the clinicopathological and prognostic significance of ING3 expression in colorectal carcinogenesis and subsequent progression. Methods: ING3 expression was examined by immunohistochemistry on tissue microarray containing colorectal non-neoplastic mucosa (NNM), adenoma and adenocarcinoma. Colorectal carcinoma tissue and cell lines were studied for ING3 expression by Western blot or RT-PCR. Results: ING3 mRNA was differentially expressed in Colo201, Colo205, DLD-1, HCT-15, HCT-116, HT-29, KM-12, SW480, SW620 and WiDr cells. Carcinomas showed significantly lower ING3 expression than matched NNM at mRNA level (P<0.05), but not at protein level. Immunohistochemically, ING3 expression was significantly decreased from NNM, adenoma to adenocarcinoma (P<0.05). ING3 expression was not correlated with age, sex, tumour size, depth of invasion, lymphatic or venous invasion, lymph node metastasis, tumour- node- metastasis staging or differentiation. Kaplan-Meier analysis indicated that ING3 protein expression was not associated the prognosis of the patients with colorectal carcinoma (P<0.05). Interpretation & conclusions: Our study showed that downregulated ING3 expression might play an important role in colorectal adenoma-adenocarcinoma sequence. Further studies are required to understand the mechanism.

The expression and signi ficance of ING3 in colorectal cancer / 实用肿瘤学杂志

Objetcvi e Inhibitor of growth TNG3 is a candidate tumor suppressor gene ,which belongs to the human ING gene family .It has been interested by scientist because of its putative roles as tumor suppressors . There is a low expression level of ING3 in a variety of tumors.However,the relationship of ING3 and the develop-ment of colorectal cancer is unclear yet .The aim of this studyis to examine the expression of ING 3 in colorectal cancer by qRT-PCR.Methods Statistical analysis was performed with the expression of ING 3 mRNA which has been evaluated in 82 matched samples comprising primary colorectal cancer and paired non -cancerous mu-cosa samples.Results In 51%colorectal cancer patients ,the expression level of ING3 was significantly lower in cancer tissue than that in normal tissue .The expression level of ING3 was closely related to pT、pM stage , and TNM stage(P<0.05).The Univariate analysis showed that the pT、pN、pM stage,TNMstage and ING3 expression levels were associated with disease -free survival(P<0.05).CRC patients with low -expression level of ING3 showed shorter disease -free survivals(P<0.05).Conclusion The expression of ING3 might contribute to the CRC development or progression .