CD25 is a novel marker of hepatic bile canaliculus.

OBJECTIVE: Although many antigens have been investigated, the method for the bile canaliculus staining using optical microscopy needs to be improved. The aim of the present study was to assess the expression pattern of a candidate marker, CD25, in normal and diseased liver tissue. METHODS: Immunohistochemistry, immunofluorescence, and immune electron microscopy assays were performed with 41 liver sections and 2 different anti-CD25 monoclonal antibodies. A polyclonal antibody against carcinoembryonic antigen (CEA) was also used to stain bile canaliculus as a control. CD25 expression levels in normal and diseased liver tissue were also determined. RESULTS: CD25 was predominantly localized at the bile canaliculus of adult and infantile liver, evidenced by both immunohistochemistry and immunofluorescence assays. The electron microscopy assay showed that there were obvious amorphous electron-dense deposits at the bile canaliculus. In contrast, the CEA-positive area included bile canaliculus as well as basolateral aspects of hepatocytes. CD25 expression levels did not differ significantly among different disease states. CONCLUSION: This study provides the first evidence that CD25 is a novel marker of bile canaliculus. Characteristics of CD25 expression may shed light on immunohistochemistry and immunofluorescence analysis of bile canaliculus in both basic and clinical hepatic investigations.

DIXDC1 targets p21 and cyclin D1 via PI3K pathway activation to promote colon cancer cell proliferation.

DIXDC1 is the human homolog of Ccd1, a recently identified DIX domain containing protein in zebrafish. It is a positive regulator in the Wnt signaling pathway functioning downstream of Wnt and upstream of Axin. Since Wnt pathway activation is correlated with human colon cancer formation and progression, the biological role of DIXDC1 in human colon cancer was examined. In the current study, up-regulation of DIXDC1 protein was detected in human colorectal adenocarcinoma tissues and was found to be correlated well with high cell proliferation index. Ectopic over-expression of DIXDC1 resulted in increased cell proliferation in vitro and accelerated tumorigenesis on nude mice in vivo. We also showed that DIXDC1 promoted G0/G1 to S phase transition concomitantly with up-regulation of cyclin D1 and down-regulation of p21 protein. DIXDC1 over-expression cells showed activation of the PI3K/AKT pathway. Both siRNA knockdown of DIXDC1 and blocking the PI3K pathway using a specific inhibitor caused G1/S phase arrest, as well as down-regulation of cyclin D1 and up-regulation of p21 in DIXDC1 over-expression colon cancer cells. Collectively, this study demonstrates that over-expression of DIXDC1 might target p21 and cyclin D1 to promote colon cancer cell proliferation and tumorigenesis at least partially through activation of the PI3K/Akt pathway.

[Clonality and Ki-67 protein expression in gastric carcinoma and precancerous lesions].

OBJECTIVE: To study the clonality of gastric carcinoma and precancerous lesions and its relationship with Ki-67 protein expression. METHODS: Formalin-fixed paraffin embedded tissues were collected from 174 cases of gastric endoscopic biopsies and surgical removed specimens. The lesional tissues were isolated by Laser Capture Microdissection. Methylation sensitive restriction enzyme (HpaII) digestion and polymerase chain reaction (PCR) were used to detect the clonality at the polymorphic human androgen receptor gene locus on the X chromosome. PCR products were analyzed by capillary electrophoresis using applied Biosystems 3730 DNA Analyzer. In addition, a two-step immunohistochemical staining EnVision method was used to detect the expression of Ki-67 protein. RESULTS: The frequency of detection of monoclonality and expression rate of Ki-67 were found increased in a stepwise fashion from gastrointestinal metaplasia, low grade intraepithelial neoplasia, high grade intraepithelial neoplasia to intestinal carcinoma (15.63%, 5/32; 22.22%, 10/45; 69.44%, 25/36 and 100.0%, 20/20; respectively). The presence of clonal proliferation was correlated with Ki-67 expression in low grade intraepithelial neoplasia (P < 0.01). CONCLUSIONS: The presence of clonal proliferation and increased Ki-67 are increasingly detected in the lesions along the multi-step gastric carcinogenesis model. Clonal status is associated with the expression rate of Ki-67 to a certain extent, suggesting a combined application of both markers may be useful in assessing early stages of gastric carcinoma.

Roles of EGFR-Stat3 signal pathway in carcinogenesis of experimental hepatoma in rats.

The purpose of this study is to investigate if the EGFR-Stat3 signal pathway contributes to the carcinogenesis of hepatoma in rats. Hepatoma was induced in rats by 3'Me-DAB as a model. EGFR, TGFalpha, Stat3, p-Stat3 in different stages of carcinogenesis were detected by immunohistochemistry and Western blot. In situ hybridization was applied to investigate the expression of Stat3 mRNA. The expressions of signal molecules were assessed by KS400 Image Analysis system. The data were statistically evaluated. EGFR, TGFalpha, Stat3 were highly expressed in the stages of liver necrosis and repairment. All hepatocellular carcinoma cases revealed elevated expression of EGFR, TGFalpha. Elevation of Stat3 mRNA and protein levels were identified, increase of activation of Stat3 was also observed. In HCC, there was positive correlation between p-Stat3 level and the expression of TGFalpha and PCNA. Increased expression of Bcl-2 (P < 0.05) coincided with elevated level of p-Stat3. Therefore, the EGFR-Stat3 signal pathway was related to the development of hepatoma in rats. TGFalpha-EGFR autocrine ring formation may lead to the activation of Stat3 and in turn, promote proliferation and regulate the transcription of genes regulating cell apoptosis and cell cycle.

[Expression and significance of hTERT mRNA in breast carcinoma and its relation to p53].

OBJECTIVE: This study was designed to investigate the significance of hTERT mRNA in breast carcinogenesis and to explore the diagnostic efficacy, and to study the effect of tumor suppressor gene p53 on the expression of hTERT mRNA. METHODS: The expression of hTERT mRNA was examined by in situ hybridization in 12 cases of normal breast tissue nearby cancer, 7 of simple ductal hyperplasia, 20 of atypical hyperplasia, 18 of ductal carcinoma in situ and 25 with invasive ductal carcinoma. The expression of p53 protein were examined by immunohistochemistry in 43 carcinomas. RESULTS: hTERT was not detected in normal breast tissue nearby cancer and simple ductal hyperplasia. The positive rate of hTERT mRNA in atypical hyperplasia, ductal carcinoma in situ and invasive ductal carcinoma were 25.0%, 83.3% and 88.0%, respectively. The prevalence and intensity of hTERT mRNA expression were much greater in carcinoma than those in simple or atypical hyperplasia and normal breast tissue nearby cancer (P < 0.05). The expression of hTERT was not correlated with tumor size and lymph node metastasis (P > 0.05). The positive correlation between hTERT mRNA and p53 was found in breast carcinoma (r = 0.5540, P < 0.01). CONCLUSION: hTERT mRNA expression is closely related to the malignant transformation of breast tissue. Semi-quantitative detection of hTERT mRNA expression in situ is helpful in differentiated diagnosis of carcinoma in situ and atypical hyperplasia. Inactivation of p53 may play a role in the transcriptive activation of hTERT gene in breast carcinoma.