Men with no sons more at risk for prostate cancer

In a new and unique study to determine if genes on the Y chromosome are involved in prostate cancer, researchers at Columbia University's Mailman School of Public Health in conjunction with Hebrew University of Jerusalem found that men who had only daughters had a higher risk of prostate cancer than men who had at least one son, thus signifying a possible defect on the father's Y chromosome. The results, published in the January 3, 2007 issue of the Journal of the National Cancer Institute, further indicate that the relative risk of prostate cancer decreases as the number of sons increases.

The researchers in the Mailman School's Department of Epidemiology analyzed the relative risk of prostate cancer by the sex of offspring among fathers registered in a family-based research cohort in Israel. From this cohort of 38,934 men, followed from the birth of their offspring (in 1964 through 1976) until 2005, the authors conclude that genes on the Y chromosome may be involved in prostate cancer risk in this population.

"We surveyed vital status and cancer incidence, and found a strong trend for a decrease in prostate cancer risk as the number of sons increased," said Susan Harlap, MD, professor of clinical Epidemiology at the Mailman School of Public Health, and the leader of the research team. "We anticipate that this finding will have a significant impact on the direction of research in this field going forward." Overall, there was a 40% increase in prostate cancer in men lacking sons.

The offspring's sex depends on whether it receives an X or a Y chromosome from the father. A man with a damaged Y chromosome will be less likely to have sons and those with a damaged X chromosome may be unable to sire daughters. "Our findings suggest that the biological significance of lack of sons