To clarify the possible role of DCC gene alteration in ovarian neoplasias, we immunohistochemically investigated 124 carcinomas, as well as 55 cystadenomas and 41 low malignant potential (LMP) tumours and compared the results with those for p53 protein expression, clinicopathological factors and survival.
We used immunohistochemical and DNA-sequencing techniques to analyze 46 ovarian carcinomas, 21 ovarian tumors of low malignant potential, and 16 solitary cystadenomas for the presence of p53 mutations.
Somatic p53 mutations were detected in only one tumor of the cystadenoma/adenofibroma series (4.2%), in contrast to 38.5% of the carcinomas, among them 57.1% of serous papillary carcinomas, and 12.5 to 22.2% of endometrioid and mucinous carcinomas.
In mucinous neoplasms; altered BRCA-1 was detected in 25 specimens; 7 of 20 (41%) of benign cystadenomas, 5 of 15 (33%) of borderline neoplasms, 9 of 20 (45%) of primary carcinoma, and 4 of 5 (80%) of the metastatic deposits.
We concluded that cystadenoma is likely to be a characteristic feature of the subgroup of families with hereditary ovarian cancers unassociated with BRCA1/BRCA2 constitutional mutations.
The mRNA expression level of p16 and RAR-β was significantly downregulated in EOC and LMP tumors than the corresponding normal tissues whereas the expression level was normal in benign cystadenomas for p16 and slightly reduced for RAR-β.
The mRNA expression level of p16 and RAR-β was significantly downregulated in EOC and LMP tumors than the corresponding normal tissues whereas the expression level was normal in benign cystadenomas for p16 and slightly reduced for RAR-β.
Changes in DNA methylation may be more important for inactivation of this gene (and perhaps other tumor suppressor genes) in LMP tumors, which lack many of the alternative mechanisms present in carcinomas. p16 expression is primarily related to mucinous differentiation in cystadenomas.
Changes in DNA methylation may be more important for inactivation of this gene (and perhaps other tumor suppressor genes) in LMP tumors, which lack many of the alternative mechanisms present in carcinomas. p16 expression is primarily related to mucinous differentiation in cystadenomas.
All six cases of normal pancreas and all but 1 of 20 cases of chronic pancreatitis expressed p16 protein, whereas 37.5% (3 of 8) of cystadenomas and 41.
All six cases of normal pancreas and all but 1 of 20 cases of chronic pancreatitis expressed p16 protein, whereas 37.5% (3 of 8) of cystadenomas and 41.
Mouse model studies also showed increased expression of AdPLA2 in xenograft tumors, estrogen-induced lung metastatic lesions of Tsc2 null leiomyoma-derived cells, and spontaneous renal cystadenomas from Tsc2+/- mice.
PARP1 levels were increased in TSC2(-) cells, xenograft tumors of rat-derived TSC2(-) cells, renal cystadenomas from Tsc2(+/-) mice, and human LAM nodules.
The observed aberrant methylation frequencies of the RASSF1A and APC gene promoters indicate that an accumulation of epigenetic events at these specific TSG promoters may be associated with the malignant transformation of benign cystadenomas and LMP tumours to carcinomas.
Although genetic and immunohistochemical analysis of precursor structures consistently revealed VHL gene inactivation and activation of HIF in the precursor lesions, only a small subset appears to progress into frank cystadenoma.
We analyzed the DNA promoter methylation status of eight tumor suppressor and cancer-related genes (p16, RARbeta, E-cadherin,H-cadherin, APC, GSTP1, MGMT, RASSF1A) in 23 benign cystadenomas, 23 low malignant potential (LMP) tumors, and 23 invasive carcinomas by methylation-specific PCR.
To address this issue, we compared the mutational status of BRAF and KRAS in both SBTs and the adjacent epithelium from cystadenomas, the presumed precursor of SBTs.
As the VHL gene is believed to function as a tumor suppressor gene, VHL gene mutations may play a role in the initiation of tumorigenesis in sporadic cystadenomas of the epididymis.
Using DNA extracted from paraffin embedded tissue, polymerase chain reaction amplification, designed restriction fragment length polymorphism analysis, and DNA sequencing, 1 cystadenoma (5%), 6 LMP tumors (30%), and 1 ovarian carcinoma (4%) demonstrated an activated Ki-ras gene.
The results demonstrated that high expression of AGBL2 was observed in 9% of cystadenomas cases, 21% of borderline tumors cases and 38% of ovarian carcinomas cases; however AGBL2 expression was not high in normal ovarian tissues (P<0.01).