Smoking Linked to Prostate Cancer

Reuters Health | 01.27.2006

Smoking influences progression and prognosis of prostate cancer through a process called aberrant hypermethylation of CpG (cytosine-phosphorothiolated guanine) sequences on related genes, a new study indicates.

Previous studies have shown a positive association between current smoking and prostate carcinoma, as well as between aberrant CpG methylation profiles of certain gene promoters and progression of prostate cancer. But the mechanism involved in these associations had not been elucidated.

Dr. Rajvir Dahiya of the Veterans Affairs Medical Center and University of California, San Francisco, and his colleagues conducted a study involving 164 prostate cancer patients (52 current, 30 former, and 82 never smokers) and 69 patients with benign prostatic hyperplasia.

The investigators examined methylation in 3 genes that they have previously studied: adenomatous polyposis coli (APC), glutathione S-transferase pi (GSTP1), and multidrug resistance 1 (MDR1). They defined a methylation score (M-score) for each sample and related it to smoking status and outcomes.

The team found that the M-score was significantly higher in current smokers than in never smokers and also found a significant correlation between pack-years of smoking and M-score in the cancer patients. In addition, they noted a significant correlation of M-score with advanced pathologic features.

The researchers conclude that smoking may influence tumor progression through CpG hypermethylation of related genes in a dose-dependent fashion.

Cancer 2006;106:79-86

Reuters Health Information 2006. © 2006 Reuters Ltd.
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