| The p28 protein purified from human 26S proteasome is identical to gankyrin protein (p28~GANK). the product of a novel gene cloned in human hepatocellular carcinoma (HCC), which is reported to be an oncoprotein binding to retinoblastoma gene product (RB), involved in the carcinogenesis of HCC.In present study, we analyzed the expression pattern of p28~GANK in HCC and attempted to elucidate the role of p28~GANK in the RB repertoire in a series of surgically resected HCCs. Particularly, the influences of p28~GANK's expressional alteration and aberrant topological or chronological distribution on RB during the development of HCC were determined. Western blot was applied to testifying the validity of the antibody of p28~GANKIn this study, we detected p28~GANK alterative expression in 55 HCCs by immunohistochemistry (IHC), and explored its association with clinicopathologic features. The mRNA expression of p28~GANK was evaluated in HCCs and 5 HCC cell lines by RT-PCR. Positive p28~GANK cytoplasmic staining was recognized in 55 HCCs. Scattered uniform p28~GANK nuclear staining in HCCs is more predominant than which in paracancerous hepatic tissues (p = 0.0001). Alterable nuclear expression of RB was found in 23 of 26 cases recruited from 55 HCCs, of which 15 decreased and 8 increased expression. The expression level of RB has no correlation with nuclear expressional level of p28~GANK. The overexpression level of p28~GANK was significantly associated with Edmonson's grade of HCC: overexpression of p28~GANK occurred in 9 of 11 (82%), 22 of 39 (56%) and 2 of 5 (40%) in I-II, III and IV graded cases respectively (p = 0.004). Thetotal expression level of p28GANK was significantly correlated with the nuclear expression of RB (r = 0.475, p = 0.019). On the other hand, there is no co-linearity relationship between p28GANK and mutated p53 expression. RT-PCR documented that was arnpijfied m au examined HCCs and HCC cell lines. Our observations suggest that p28GANK overexpression is initiated in early stage of HCC development. The whole cellular activated p28GANK expression, but not nuclear portion only, participates in the tendency of hyperphosphorylation inactivation of excess nuclear RB in the process of HCC carcinogenesis. The translocated p p28GANK in nucleus was just a wizard guiding the hyperphosphorylation process of RB.To investigate the sensitivity, specificity, and spatial distribution of the product of p28 gene (p28GANK protein) in human hepatocellular carcinoma (HCC) and nonhepatocellular carcinomas in relation to immunostaining with Cytokeratin 18 (CK18), a -fetoprotein (AFP) and Hepatocyte paraffin 1 (HepParl). Method: In this retrospective study, formalin-fixed paraffin-embedded tissues from 24 HCCs, 5 intrahepatic cholangiocarcinomas (ICC), 5 combined hepatocellular cholangiocarcinomas (C-HCC-CC) and 9 metastatic hepatic carcinomas (MHC) were immunostained for p2gGANK as wejj as cKig5 App an(j HepParl. Only cases with more intensified staining in carcinoma contrast to the adjacent liver tissues were accepted as positive. Result: In HCC, p28GANK expressed restrictively in hepatocytes of both para-lesion and carcinoma liver tissues, while absent in the bile duct epithelial cells, Kupffer cells and other interstitial cells. The positive staining of p28GANK was noted in 16 (66.7%) specimens of HCC and 3 (60.0%) specimens of C-HCC-CC, and no specific lesion staining was found... |
