HOUSTON: A new molecular tag discovered by scientists at The University of Texas M. D. Anderson Cancer Center may help doctors decide which breast cancer patients need more aggressive treatment and which can forego the potentially toxic course of chemotherapy.

Khandan Keyomarsi, Ph.D., associate professor in experimental radiation at M. D. Anderson, and her colleagues report in the New England J ournal of Medicine that high levels of a protein called cyclin E are closely associated with aggressive, invasive breast cancer. The study, conducted with tissue samples of current or former breast cancer patients, appears to show that cyclin E is a much better predictor of patient outcome than any current predictive marker. However, says Keyomarsi, the study must be repeated with newly diagnosed patients to determine its true predictive value.

The ability to predict which breast cancer tumours will recur or spread throughout the body is an important aspect of breast cancer treatment, says Keyomarsi. Currently, the prognosis for women diagnosed with breast cancer is determined by whether tumour cells have spread to lymph nodes. But some women who have cancer cells in the lymph nodes never have a recurrence, while others whose cancer has not spread do have a recurrence. Yet many women, after discussions with their doctors, opt to undergo grueling chemo­therapy in hopes of ensuring any rogue cancer cells that may be present are killed. If an accurate predictive marker were available, many women could be spared chemotherapy, she says.