Expression of DNA-repair proteins and their significance in pancreatic cancer and non-cancerous pancreatic tissues of Sprague-Dawley rats.

BACKGROUND: To establish a model of pancreatic cancer induced by 7,12-dimethylbenzantracene (DMBA) in Sprague-Dawley (SD) rats, and detect the expression of DNA-repair proteins (MGMT, ERCC1, hMSH2, and hMLH1) and their significance in pancreatic cancer and non-cancerous pancreatic tissues of SD rats. METHODS: DMBA was directly implanted into the parenchyma of rat pancreas (group A and group B), and group B rats were then treated with trichostatin A (TSA). The rats in both groups were executed within 3 to 5 months, and their pancreatic tissues were observed by macrography and under microscopy. Meanwhile, the rats in the control group (group C) were executed at 5 months. Immunohistochemistry was used to assay the expression of MGMT, ERCC1, hMSH2, and hMLH1. RESULTS: The incidence of pancreatic cancer in group A within 3 to 5 months was 48.7% (18/37), including 1 case of fibrosarcoma. The incidence of pancreatic cancer in group B was 33.3% (12/36), including 1 case of fibrosarcoma. The mean of maximal diameters of tumors in group A was higher than that in group B (P <0.05). No pathological changes were found in pancreas of group C and other main organs (except pancreas) of group A and group B. No statistical differences were found among the positive rates of MGMT, ERCC1, hMSH2, and hMLH1 in ductal adenocarcinoma and non-cancerous pancreatic tissues of group A (P >0.05). The positive rates of MGMT, ERCC1, hMSH2, and hMLH1 were significantly lower in ductal adenocarcinoma than those in non-cancerous tissues of group B (P ≤0.05). All pancreas of group C had positive expression of MGMT, ERCC1, hMSH2, and hMLH1 and two cases of fibrosarcoma showed a negative expression. CONCLUSIONS: DMBA, directly implanted into the parenchyma of pancreas, creates an ideal pancreatic cancer model within a short time. TSA might restrain DNA damage related to the genesis and growth of pancreatic cancer in rats. The DNA-repair proteins, including MGMT, ERCC1, hMSH2, and hMLH1, might play an important role in the genesis of pancreatic cancer induced by DMBA in rats.

Clinicopathological significance of DNA fragmentation factor 45 and thyroid transcription factor 1 expression in benign and malignant lesions of the gallbladder.

Gallbladder cancer (GBC) is one of the most aggressive tumors; we examined the expression level of DNA fragmentation factor 45 (DFF45) and thyroid transcription factor 1 (TTF-1) in benign and malignant lesions of the gallbladder by immunohistochemistry. The results were correlated with clinicopathological features and prognosis. DNA fragmentation factor 45 and TTF-1 expression was significantly higher in gallbladder adenocarcinomas than in the corresponding peritumoral tissues (χ²DFF45 = 6.92, χ²TTF-1 = 8.68, ps < 0.01), polyps (χ²DFF45 = 4.49, χ²TTF-1 = 5.35, ps < 0.05), and chronic cholecystitis (χ²DFF45 = 12.98, χ²TTF-1 = 17.74, ps < 0.01). Negative expression of DFF45 and TTF-1 was significantly associated with tumor differentiation, tumor mass, lymph node metastasis and invasion of adenocarcinomas (p < 0.05). Univariate Kaplan-Meier analysis showed that elevated expression levels of DFF45 and TTF-1 (p < 0.05) were closely associated with increased overall survival. In addition, the average survival time of patients with DFF45(+) TTF-1(+) tumors was significantly higher than those with DFF45(-) TTF-1(-) tumors (p < 0.05). Finally, multivariate Cox regression analysis showed that negative expression of DFF45 and TTF-1 was an independent prognostic predictor in gallbladder adenocarcinoma (p < 0.05). The expression of DFF45 and/or TTF-1 is closely related to the carcinogenesis, progression, clinical behavior and prognosis of gallbladder adenocarcinomas. DNA fragmentation factor 45 and TTF-1 could be progression-associated genes correlating with good prognosis in GBC.

[Expression of annexin A1 (ANXA1) and A2 (ANXA2) and its significance in benign and malignant lesions of gallbladder].

OBJECTIVE: To study the expression levels of ANXA1 and ANXA2 and elucidate their clinicopathological significance in adenocarcinoma, peritumoral tissues, adenomatous polyp and chronic cholecystitis of gallbladder. METHODS: EnVision(TM) immunohistochemical staining was used to detect the expression of ANXA1 and ANXA2 in paraffin-embedded tissue sections from resected specimens of adenocarcinoma (n = 108), peritumoral tissue (n = 46), adenomatous polyp (n = 15) and chronic cholecystitis (n = 35). RESULTS: The positive rates and scores of ANXA1 and ANXA2 were significantly higher in adenocarcinoma (59.3%, 56.5%; 3.2 ± 0.9, 3.4 ± 0.8) than those in peritumoral tissues (34.8%, 1.1 ± 0.8, P < 0.01; 30.4%, 1.0 ± 0.8, P < 0.01), adenomatous polyp (26.7%, 0.9 ± 0.7, P < 0.05 or P < 0.01; 26.7%, 0.9 ± 0.8, P < 0.05 or P < 0.01) and chronic cholecystitis (17.1%, 0.7 ± 0.9, P < 0.01; 20.0%, 0.8 ± 0.8, P < 0.01). The benign lesions with positive ANXA1 and/or ANXA2 expression showed mild to severe atypical hyperplasia of the gallbladder epithelium. The positive rates of ANXA1 and/or ANXA2 were significantly lower in the well-differentiated adenocarcinoma, in a maximal diameter of < 2 cm, with no metastasis to lymph nodes and no invasion to surrounding tissues than those in the moderately or poorly-differentiated adenocarcinoma, in a maximal diameter of ≥ 2 cm, with metastasis to lymph nodes and invasion in surrounding tissues (P < 0.05 or P < 0.01). A high consistence was found between the expression levels of ANXA1 and ANXA2 (χ(2) = 67.84, P < 0.01), and a close positive correlation between the scores of ANXA1 and ANXA2 (r = 0.78, P < 0.01) in gallbladder adenocarcinoma. Kaplan-Meier analysis and multivariate Cox regression analysis showed that ANXA1 or ANXA2 was not an independent prognostic predictor in gallbladder adenocarcinoma. CONCLUSION: The expression levels of ANXA1 and/or ANXA2 may be important biological markers in the carcinogenesis, progression and biological behaviors of gallbladder adenocarcinoma.

Expression of Ezrin, HGF, C-met in pancreatic cancer and non-cancerous pancreatic tissues of rats.

BACKGROUND: Recent studies have confirmed that the expression of Ezrin, hepatocyte growth factor (HGF) and its receptor (C-met) is related to the genesis, progress, invasion and metastasis of some malignant tumors. Researches have also found that the biological function of Ezrin is closely related to HGF/C-met in malignant tumors. However, there is no report on the expression levels of Ezrin, HGF and C-met in rat pancreatic cancer induced by dimethylbenzanthracene (DMBA). This study aimed to detect the expression of Ezrin, HGF and C-met in rat pancreatic cancer and non-cancerous pancreatic tissues, and assess its effect in cancer induction by DMBA. METHODS: Ninety Sprague-Dawley rats were divided into 3 groups randomly: 40 in a pancreatic cancer model group (group A), 40 in a trichostatin A (TSA) intervention group (group B), and 10 in a control group (group C). DMBA was directly implanted into the parenchyma of rat pancreas in group A+group B. The rats of group B were treated with 1 ml of TSA saline solution (1 µg/ml) via intraperitoneal injection weekly. The carcinogenesis of rats executed within 3-5 months in groups A and B was observed by macrograph and microscopy. Meanwhile, the rats in group C were executed within 5 months. The EnVisionTM immunohistochemistry for detecting the expression levels of Ezrin, HGF and C-met was used in paraffin-embedded sections of the pancreatic specimens. RESULTS: The incidence of pancreatic cancer in group A was 48.6% and in group B 33.3%. The maximal diameter of tumor mass was significantly larger in group A than that in group B (P<0.05). No pathological changes were observed in the pancreas of group C and other main organs of groups A and B. The positive rates of Ezrin, HGF and C-met were significantly higher in ductal adenocarcinoma than in non-cancerous pancreatic tissues of groups A and B (P<0.01). The positive rates of Ezrin, HGF and C-met were significantly higher in ductal adenocarcinoma of group A than those in non-cancerous pancreatic tissues of group A (P<0.05), but there was no significant difference in group B (P>0.05). The positive rates of Ezrin, HGF and C-met in non-cancerous pancreatic tissues proved mild to severe atypical hyperplasia of the ductal epithelia. The pancreas of group C and 2 cases of fibrosarcoma showed the negative expression of Ezrin, HGF and C-met. There was a trend of consistency in the expression of Ezrin, HGF and C-met in ductal adenocarcinoma (P<0.05 or P<0.01). CONCLUSIONS: DMBA directly implanted into the parenchyma of the pancreas can produce a model of pancreatic cancer with a high incidence in a short time. TSA might inhibit the carcinogenesis and growth of pancreatic cancer, and its effects may be related to the inhibition of the expression of Ezrin, HGF and C-met during the process. Ezrin, HGF and C-met may have positive effects on the carcinogenesis of rat pancreas.