WWOX gene expression and aberrant CpG island hypermethylation of WWOX gene in breast cancer / 中华普通外科杂志

ABSTRACT

Objective To evaluate the expression of WWOX gene in breast cancer and its relation to hypermethylation of WWOX gene CpG island. Methods The expression of WWOX protein was evaluated by immunohistochemical staining in breast cancer cell line and breast cancer tissues.Methylation specific PCR(MSP)was used to check whether it Was methylated in the promoter and exon 1 of WWOX.Results Deletion in the WWOX expression was observed more frequently in invasive breast tumors,(32.2%)than normal breasttissues(5.4%)(P＜0.01).20.3% of premenopause eases were completely negative for WWOX expression compared to 57.2% of postmenopause breast carcinomas(P＜0.01).Furthermore,23.1% of Stage Ⅰ(6/26),28.6%of Stage Ⅱ(10/35),46.2%of Stage Ⅲ(12/26)tunlors showed negative WWOX protein expression.In breast cancer specimens.methylation rate of promoter and exon 1 CpG island of WWOX gene was 55%and 45%respectively.Whereas.WWOX CpG islands of normal mammary tissues were completely unmethylated in all cases.CpG islands of WWOX promoter and exon 1 were methylated in MDA-MB-231 cell line but not MCF-7 cell.Conclusions Some deletion in WWOX expression is common in breast cancer and methylation of WWOX DNA CpG islands plays a crucial role in the silence of WWOX.WWOX may play a role in the carcinogenesis and development of breast cancer.