查看文章

DNA methylation appears to play an important role in both physiological and experimentally modified gene expression, and alterations in DNA methylation have been described in animal tumor models and in transformed cells and tumor cell lines. However, there have been comparatively few reports on DNA methylation in primary human malignancies, and these reports are somewhat contradictory. While individual genes have shown hypomethylation in colon cancer and premalignant adenomas as well as in lung cancer, other genes have shown increased methylation, and absolute measures of 5-methylcytosine content have shown decreases in malignancies but not in premalignant adenomas. We have used a sensitive quantitative measurement of 5-methylcytosine content by high performance liquid chromatography revealing an unequivocal hypomethylation of tumor DNA. An average of 8 and 10% reduction …