Mesothelin gene expression and promoter methylation/hypomethylation in gynecological tumors

PURPOSE

Mesothelin is a cell surface glycoprotein that is present on normal mesothelial cells and overexpressed in several cancers. In this study, we investigated the methylation/hypomethylation status in the promoter region of the mesothelin gene in gynecological tumors.

METHODS

Forty-four ovarian tumor specimens and 16 cases of uterine endometrial carcinoma, and normal tissue specimens were used. Monoclonal antibody (5B2) was employed for the immunohistochemical analysis. The methylation-sensitive single-nucleotide primer extension (Ms-SNuPE) technique was used to quantify the methylation/hypomethylation status at 20 CpG sites in the mesothelin promoter region.

RESULTS

Mesothelin was expressed in 100% of serous cystadenocarcinoma and 100% of serous borderline tumor of the ovary. None of the germ cell tumors and sexcord-stromal tumors was immunoreactive. Fifty percent of endometrial carcinoma was immunoreactive for mesothelin. The average methylation of CpG sites in ovarian tumors ranged from 6-56% (median: 31%) in mesothelin-positive and 13-79% (median: 43%) in mesothelin-negative samples. In endometrial tumors, the average methylation ranged from 5-52% (median: 28%) in mesothlin-positive and from 15-67% (median: 22%) in mesothlin-negative samples. A correlation was found between mesothelin expression and the average methylation/hypomethylation status as well as methylation/hypomethylation status at four of 20 CpG sites in ovarian samples. No correlation was found in endometrial samples.

CONCLUSION

We detected diverse levels of methylation/hypomethylation at CpG sites in the mesothelin promoter region in ovarian and endometrial tumors. We speculate that, although methylation/hypomethylation changes may affect its transcription, other mechanisms may synergically operate in tissue-specific expression and tumor-related mesothelin overexpression.

Aurora kinase B is a predictive factor for the aggressive recurrence of hepatocellular carcinoma after curative hepatectomy

BACKGROUND

Patterns of cancer recurrence hold the key to prognosis after curative resection. This retrospective study aimed to identify a predictor and therapeutic candidate for aggressive recurrence of hepatocellular carcinoma (HCC).

METHODS

Primary HCC tissues from 107 patients who had curative resection were analysed. Genome-wide gene expression profiles were investigated using a microarray technique, and clustering analysis was carried out based on the first diagnosis of recurrence according to the Milan criteria. Immunohistochemical expression and array-based comparative genomic hybridization (array-CGH) were also assessed.

RESULTS

Microarray analysis revealed overexpression of Aurora kinase B, a chromosome passenger protein kinase, as the most significant predictor of the aggressive recurrence of HCC. Aurora kinase B protein expression was significantly associated with aggressive recurrence (P < 0.001) and prognosis (P < 0.001). Multivariable analysis identified Aurora kinase B as the only independent predictor of aggressive recurrence of HCC (P = 0.031). Array-CGH analysis showed that genomic instability was closely related to Aurora kinase B expression (P = 0.011).

CONCLUSION

Aurora kinase B is an effective predictor of aggressive HCC recurrence, in relation to the genomic instability. It might be worth considering as a molecular target for the adjuvant therapy of HCC.