Q:   If so, what is the frequency, or average likelihood, that they'll develop a certain cancer?
A:   Individuals carrying germline mutations in PTEN are predisposed to breast cancer (up to 50 percent lifetime risk in women); thyroid cancer (10 percent lifetime risk); and endometrial cancer (perhaps 6-10 percent lifetime risk in women). It is believed that other cancers are associated with germline PTEN mutations, but there is little epidemiologic data to back these up.

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Q:   What are gene therapies for those whose PTEN genes have become damaged or mutated?
A:   There are no gene therapies for PTEN-related disorders. In general, gene therapy for cancer does not work and has not worked even after two or more decades of such research.

What we clinical cancer geneticists do is to try to identify individuals with germline PTEN mutations even before they develop cancer, so-called predictive testing, so that clinical surveillance and/or prophylactic surgery can be instituted.

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Q:   What other type of research is being conducted related to the PTEN gene?
A:   There are many active research programs targeting PTEN in many labs around the world. Describing each would take more than a book. PTEN is the hottest molecule since p53. I daresay that PTEN has usurped p53's title of "Master Molecule."

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Q:   Could you offer any other elaboration on your work that you feel is important?
A:   We are not only studying PTEN from a genetic point of view, but are dissecting the workings of PTEN from a multidisciplinary approach. In addition to genetic inactivation of PTEN, we are looking into nontraditional mechanisms of PTEN inactivation. This type of bedside-to-bench-to-bedside approach is important so that our patients will quickly benefit from our studies.

Dr. Eng is the director of the Clinical Cancer Genetics Program and the Division of Human Genetics as well as professor of medicine at Ohio State University. She is one of the world's leading experts on PTEN.

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