[Novel methylation and expression markers associated with breast cancer]

We have developed a modification of methylation sensitive arbitrarily primed PCR, one of the methods of differentially methylated CpG islands in cancer cells genomes screening. Seven genes undergoing abnormal epigenetic regulation in breast cancer, SEMA6B, BIN1, VCPIP1, LAMC3, KCNH2, CACNG4 and PSMF1, have been identified by this method. Methylation and loss of expression frequencies were evaluated for each of the identified genes on 100 paired (cancer/morphologically intact control) breast tissue samples. Significant frequencies of abnormal methylation were detected for SEMA6B, BIN1, and LAMC3 (38%, 18%, and 8% correspondingly). Methylation of the above genes was not characteristic for morphologically intact breast tissues. Downregulation of SEMA6B, BIN1, VCPIP1, LAMC3, KCNH2, CACNG4 and PSMF1 in breast cancer was as frequent as 44-94% by real-time PCR expression assay. The most pronounced functional alterations were demonstrated for SEMA6B and LAMC3 genes, which allows recommending their inclusion into the panels of carcinogenesis diagnostic panels. Fine methylation mapping was performed for the genes most frequently methylated in breast cancer (SEMA6B, BIN1, LAMC3), providing a fundamental basis for the development of effective methylation tests for these genes.