To determine the implication of aberrant methylation, one of the most frequent mechanisms of silencing the tumor suppressor or cancer-related genes, we examined the methylation status of DLC-1 promoter region in breast cancer cell lines and primary breast tumors.
Genomic deletion of DLC-1 was observed in 40% of primary breast tumors, whereas reduced or undetectable levels of DLC-1 mRNA were seen in 70% of breast, 70% of colon, and 50% of prostate tumor cell lines To see whether DLC-1 expression affects cell growth and tumorigenicity, two breast carcinoma cell lines lacking the expression of endogenous gene were transfected with the DLC-1 cDNA.