Fig. 1

CLDN6 expression is down-regulated drastically by DNA hypermethylation in breast cancer tissues and MCF-7 cells. a CLDN6 expression was significantly higher in breast pericarcinomatous tissues than that in breast cancer tissues by western blot. From lane 1 to lane 7 were represented of different tissue samples. P = 0.021 < 0.05. b The expression of CLDN6 in HBL-100、MCF-7 and COC1 cells (as tissue-specific control), determined by RT-PCR and Western blot assay. Differently with HBL-100 cells, CLDN6 expression was undetectable or low levels in MCF-7 cells. c CLDN6 DNA methylation status was determined in breast pericarcinomatous tissues and breast cancer tissues by MSP. (D) CLDN6 DNA methylation status was determined by MSP analysis in HBL-100, MCF-7 and COC1 cells. CLDN6, claudin-6; MSP, Methylation-Specific PCR