The gene, called hiwi, belongs to the piwi family of genes discovered in 1997 in the laboratory of Haifan Lin, Ph.D., an associate professor of cell biology at Duke and senior author of the new study in Oncogene, a science journal published by the Nature Publishing Group.

Lin's new research, which was funded by the National Institutes of Health, shows that 63 percent of men, who inherit the overactive form of the hiwi gene, could develop seminoma, which is a testicular cancer that originates from reproductive cells.

According to the National Cancer Institute, testicular cancer accounts for about 1 percent of all cancers in men. Testicular cancer is the most common form of cancer in Caucasian men between the ages of 15 and 45, Lin said.

Testicular tumors usually occur in reproductive cells, which are called germ cells. The tumors are usually malignant and are grouped into two main classes: seminoma and nonseminoma. Nonseminomas tend to be more aggressive than seminomas and in most cases, quickly spread to the lymph nodes.

Lin found that in seminomas, the reproductive stem cells expressed the hiwi gene at an unusually high rate. The cells then divided and multiplied at an equally high rate, which, Lin said, is an indication of the development of cancer. On the other hand, Lin suspects that an underactive or non-active hiwi gene can cause sterility in men because the same gene in drosophila and mice, called piwi and miwi, respectively, are known to cause sterility, said Lin who also is affiliated with Duke's Comprehensive Cancer Research Center.

The gene activity in the cancer samples was up to 16 times higher than that of a healthy patient. Although the patient sample size is small, the d
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Contact: Amy Reyes
a.reyes@duke.edu
919-668-7837
Duke University Medical Center
5-Jun-2002