Aberrant methylation of the cyclin D2 promoter in primary small cell, nonsmall cell lung and breast cancers.

DNA methylation alteration of several genes contributes to human tumorigenesis. Cyclin D2, a member of the D-type cyclins, is implicated in cell cycle regulation and malignant transformation. In our study, we examined the methylation status of the cyclin D2 promoter in small cell lung cancer (SCLC), nonsmall cell lung cancer (NSCLC), breast tumors and tumor cell lines.

Loss of heterozygosity in benign breast epithelium in relation to breast cancer risk.

The multistage model of breast carcinogenesis suggests that errors in DNA replication and repair generate diversity in the breast epithelium (the mutator phenotype), resulting in selection and expansion of premalignant clones with an acquired survival advantage. We measured loss of heterozygosity (LOH) in breast epithelial cells obtained by random fine-needle aspiration (FNA) biopsy from 30 asymptomatic women whose risk of breast cancer had been defined by the Gail model. Polymorphic microsatellite markers were selected on the basis of their relevance to breast cancer.