Canadian researchers say they’ve identified 153 more genes that promote breast cancer growth, and have found that blocking one gene in particular can stop estrogen-driven breast cancer -- at least in the laboratory."Identification of these genes is a slow process,” said co-researcher Vincent Giguere. “So far, one per year has been discovered, about 20 in all are known. What we did was use data from the Human Genome Project to engineer a microchip that has about 19,000 pieces of genes on them."The team then narrowed down where the estrogen receptor was in the genome of breast cancer cells, and identified a large number of genes that respond to the hormone.The discovery of one gene in particular, named FOXA1, is of importance, Giguere said, because it appears to facilitate estrogen’s effects on cancer cells. FOXA1 was required for the estrogen receptor to activate the growth of breast cancer cells.About two-thirds of breast tumors are estrogen-receptor positive, according to the American Cancer Society, meaning they need estrogen to grow."What we did then was remove FOXA1 protein from the cell,” said Giguere, the director of the molecular oncology group at McGill University Health Centre in Montreal. “When we do that, the cancer cells cannot grow in response to the estrogen anymore. So, we have identified a gene that is responsible for the growth of breast cancer cells. It dictates how the estrogen hormones can make the cells grow.""If we can inactivate FOXA1, we can stop the cancer cells from growing,” Giguere predicted.The findings appear in this week’s issue of the Proceedings of the National Academy of Sciences.
