Reduced membranous and ectopic cytoplasmic expression of beta -catenin correlate with cyclin D1 overexpression and poor prognosis in pancreatic cancer

N/A

N/A

β-catenin up-regulates the expression of cyclinD1, c-myc and MMP-7 in human pancreatic cancer: Relationships with carcinogenesis and metastasis

AIM: To investigate whether abnormal expression of β-catenin in conjunction with overexpression of cyclinD1, c-myc and matrix metalloproteinase-7 (MMP-7) correlated with the carcinogenesis, metastasis and prognosis of pancreatic cancer, and to analyze the relationship of β-catenin expression with cyclinD1, c-myc and MMP-7 expression.

METHODS: Using immunohistochemistry, we examined the expression of β-catenin, cyclinD1, c-myc and MMP-7 in 47 pancreatic adenocarcinoma tissues, 12 pancreatic intraepithelial neoplasia (PanIN) and 10 normal pancreases, respectively. Proliferation cell nuclear antigen was also tested as the index of proliferative activity of pancreatic cancer cells.

RESULTS: In 10 cases of normal pancreatic tissues, epithelial cells showed equally strong membranous expression of β-catenin protein at the cell-cell boundaries, but the expression of cyclinD1, c-myc and MMP-7 was negative. The expression of β-catenin, cyclinD1, c-myc and MMP-7 in PanIN and pancreatic adenocarcinoma tissues had no significant difference [6/12 and 32/47 (68.1%), 6/12 and 35/47 (74.5%), 5/12 and 33/47 (70.2%), 7/12 and 30/47 (63.8%), respectively]. The abnormal expression of β-catenin was significantly correlated to metastasis and one-year survival rate of pancreatic cancer, but had no relation with size, differentiation and cell proliferation. The expression of cyclinD1 was correlated with cell proliferation and extent of differentiation, but not with size, metastasis and one-year survival rate of the pancreatic cancer. The expression of c-myc was not correlated with size, extent of differentiation, metastasis and 1-year survival rate, but closely with cell proliferation of pancreatic cancer. The overexpression of MMP-7 was significantly associated with metastasis and 1-year survival rate of pancreatic cancer, but not with size, extent of differentiation and cell proliferation. There was a highly significant positive association between abnormal expression of β-catenin and overexpression of cyclinD1, c-myc and MMP-7 not only in PanIN (r = 1.000, 0.845, 0.845), but also in pancreatic cancer (r = 0.437, 0.452, 0.435).

CONCLUSION: The abnormal expression of β-catenin plays a key role in the carcinogenesis and progression of human pancreatic carcinoma by up-regulating the expression of cyclinD1, c-myc and MMP-7, resulting in the degradation of extracellular matrix and uncontrolled cell proliferation and differentiation. β-catenin abnormal expression and MMP-7 overexpression may be considered as two useful markers for determining metastasis and prognosis of human pancreatic cancer.

E-cadherin and β-catenin expression in pancreatic intraepithelial neoplasia and pancreatic adenocarcinoma

AIM: To investigate the significance of abnormal E-cadherin (E-Cad) and β-catenin (β-Cat) expression in pancreatic intraepithelial neoplasia (PanIN) and pancreatic adenoc-arcinoma.

METHODS: One hundred and fifty-six cases of pancreatic samples, which were surgically removed and autopsied in Changhai Hospital from January 2001 to December 2003, were retrospectively studied. Tissue microarray blocks containing 129 PanIN-1A lesions, 104 PanIN-1B lesions, 22 PanIN-2 lesions, 11 PanIN-3 lesions, and 121 cases of pancreatic ductal adenocarcinoma and corresponding para-cancerous tissues were constructed. EnVision method of immunohistochemistry was used to detect the E-Cad and β-Cat expression in the above tissues. The correlation between the abnormal E-Cad, β-Cat expression and clinicopathological parameters was analyzed.

RESULTS: The rate of E-Cad abnormal expression was significantly higher in ductal adenocarcinomas than that in PanIN lesions and normal ducts (64.5% vs 32.3%, 64.5% vs 0%, P < 0.05), and the rate of E-Cad abnormal expression was in significant relation to differentiation, lymph node metastasis and perineural invasion of pancreatic adenocarcinoma (P < 0.05). There was remarkably increase of the E-Cad cytoplasmic expression in PanIN lesions and ductal adenocarcinomas compared with that in normal ducts (21.8%, 34.7% vs 1.5%; P < 0.05). The rate of β-Cat abnormal expression was found to relate to lymph node metastasis and perineural invasion of pancreatic adenocarcinoma (P < 0.05). The expression of β-Cat cytoplasm and/or nucleus was significant in high-grade PanIN lesions (27.3%) and ductal adenocarcinomas (29.8%) compared with those in low grade PanIN lesions and normal ducts (3.0%, 2.3%; P < 0.05). There was a positive relationship between the E-Cad and β-Cat expression in PanIN lesions and ductal adenocarcinomas (P < 0.01, P < 0.05).

CONCLUSION: There was aberration in the expression of the E-Cad and β-Cat in PanIN lesions and ductal adenocar-cinomas, suggesting that E-Cad and β-Cat not only relate to the biological behaviour and prognosis of pancreatic cancer, but also get involved in pancreatic carcinogenesis.