Biological marker predicts chemotherapy response
Researchers at the University of California have discovered that measuring the levels of a particular protein in breast cancer cells may indicate whether a woman will respond to the most commonly prescribed chemotherapy drugs. Amy S Lee, professor of biochemistry and molecular biology at the University of Southern California, USC/Norris Comprehensive Cancer Center, successfully isolated the gene that makes a protein called GRP78 in 1980.
Now her team have built on that research to discover that high levels of GRP78 seem to protect cancer cells from a common chemotherapy regimen based on a drug called Adriamycin, a topoisomerase inhibitor. The GRP78 protein normally helps protect cells from dying, particularly when they are under stress from a lack of glucose. Professor Lee and her fellow researchers studied 432 women with stage II or III breast cancer treatment, 209 of which received Adriamycin-based chemotherapy. A total of 127 tumor samples were gathered prior to chemotherapy, the study of which revealed 67 per cent had high levels of GRP78. Further analysis of the patients' records showed that those whose tumors had higher levels of GRP78 were more likely to have had the cancer recur. About half of women whose breast cancer is treated with standard chemotherapy have their cancer return within five years. The study showed that the return of tumours was particularly likely if the women received Adriamycin-based chemotherapy and no further treatment with the chemotherapy drug taxane, regardless of their tumor stage. "GRP78 will be one more bio-marker to help us offer designer medicine ? treatments that are tailored to the patient's cancer instead of one-size-fits-all," professor Lee said. It is hoped that the research will help the development of treatments for other cancers and a study into the GRP78 proteins effect on prostate cancer treatment is currently underway. Professor Lee's findings are published as a "Priority Report" in the August 15 issue of Cancer Research.
Patient information about breast cancer chemotherapy