The Reporter: Oct 1994, Vol.5, No.3
Research Notes

HIV Study

A Columbia study has found that the continued practice of safe sex among gay men could prevent the spread of the HIV virus in the gay community, but any increase in unsafe sex practices could allow the epidemic to persist and be passed to new generations of gay men.

The study, reported in the August issue of the American Journal of Epidemiology, was conducted jointly by two epidemiologists, Dr. Martina Morris, assistant professor of sociology, and Laura Dean, associate research scientist at the School of Public Health.

Homosexual men in New York City now report an average of one new unsafe partner per year, down from more than 11 a decade ago, according to the Longitudinal AIDS Impact Project, a seven-year behavior study of New York City gay men directed by Ms. Dean. To determine the long-term effect of this dramatic drop on HIV transmission in AIDS epicenters, such as New York and San Francisco, Ms. Dean and Dr. Morris constructed a mathematical model based on data from the AIDS impact project. The model tracks the gay male population infected with HIV from 1980 to present and projects how widespread HIV will become in this group through 2030.

"We found the current sexual behavior of gay men to be right on the epidemic boundary so that HIV potentially could fade out under the right conditions or proliferate if there is even a small increase in unsafe sex habits," says Dr. Morris.

"The good news is that if safer sex is maintained and infection from other sources like injection drug use is prevented, our results indicate that the HIV epidemic could fade out among gay men. But this will not happen quickly. Even under the most optimistic scenario, it would take more than 50 years. The bad news is that it only takes an average of one more unsafe partner to keep the epidemic going strong. The future of the epidemic appears to be highly sensitive to changes in current behavior patterns. A single individual who has one more unsafe partner puts himself at slight increased risk, but if all individuals make this choice, there is a synergistic effect and everyone's risk would be dramatically increased."

Ovarian Cancer Consensus

In 1994, approximately 24,000 new cases of ovarian cancer will be diagnosed and 13,600 women will die of the disease, making ovarian cancer the leading cause of death from gynecological malignancies in the United States.

Dr. Carolyn Westhoff, associate professor of clinical obstetrics and gynecology and of epidemiology, was among the top researchers in the field of ovarian cancer invited to make a presentation to the NIH Consensus Development Conference on Ovarian Cancer Screening, Treatment, and Follow-up. The consensus panel issued its conclusions and recommendations regarding ovarian cancer after hearing scientific data presented by Dr. Westhoff and 24 other experts. Dr. Westhoff addressed screening initiatives for ovarian cancer.

"The point of screening is to change the outcome of a disease," says Dr. Westhoff. Detection alone is not enough.

"On top of the general fear of cancer, the media attention given to Gilda Radner's death created a paralyzing anxiety that is out of proportion to actual cases of ovarian cancer. Ovarian cancer is very rare, affecting one woman in 10,000 per year," says Dr. Westhoff.

"We live in a world of optimists where doctors want to do something, and patients expect the medical community to respond, but so far screening for ovarian cancer simply isn't effective. A negative screening test may comfort a woman who worries about ovarian cancer, but it doesn't change the disease outcome. A false positive screening test necessitates surgery, and any surgical procedure has inherent risks as well as economic costs."

As a gynecologist and epidemiologist, Dr. Westhoff brings a unique and pragmatic perspective to the discussion of screening. She recommends that screening be evaluated quantitatively to determine its value to public health. She advises women who are concerned about their risk to enroll in a clinical trial to evaluate screening tests and treatment modalities.

Wilms' Tumor Gene Research

New findings about a gene implicated in Wilms' tumor, a common childhood kidney cancer, could lead to less toxic treatment for the disease and provide further evidence for a completely new mechanism of how cells can become cancerous.

Most children can be treated successfully with surgery and chemotherapy, but the treatment produces negative side effects, including immunosuppression, low blood counts, nausea, bleeding, and baldness.

"The treatment of Wilms' tumor is one of the successes of modern oncology," says Dr. Benjamin Tycko, P&S assistant professor of pathology. "But a thorough understanding of the biological basis underlying the formation of the tumor might allow ultimately for the development of new treatments with less severe side effects."

Dr. Tycko's research on the gene is important also because it provides novel insights into the process by which cells become cancerous. The new Wilms' tumor gene, H19, is a member of the hot, new class of cancer-causing genes called tumor suppressors, which means the gene's absence leads to cancer.

Dr. Tycko believes he has identified a candidate gene implicated in Wilms' tumor, but other studies must prove his finding more rigorously. "There still may be other genes near the H19 gene that when silenced are involved in the tumor progression," he said. Dr. Tycko and his laboratory are doing more genetic analyses of the H19 region on chromosome 11 to attempt to home in on these other genes. He also is investigating whether H19 is implicated in other cancers.

Dr. Tycko's lead collaborator in recent research is Dr. Thomas Moulton, P&S assistant professor of oncology.