Dr. Perou has been at the forefront of cancer genetics, helping to lead the charge to discover that breast cancer is not just one disease, but in fact several types of diseases. Perou’s research has greatly affected the treatment of women with a certain type of breast cancer – basal-like breast cancer – one that’s been shown to affect about 15 to 20 percent of all breast cancer patients – up to about 45,000 new breast cancer cases diagnosed every year.
Early in Perou’s career, he was part of a group of researchers who discovered new subtypes of breast cancer using genome analysis technologies. One of the subtypes uncovered is basal-like breast cancer, a type of cancer that Perou has gone on to further research throughout his career. In 2003, Perou and collaborators showed that the subtype is the most common cancer type in women with the BRCA1 gene mutation. And in 2005, he and collaborators showed that the subtype is chemotherapy-sensitive. Then, in findings published in the Journal of the American Medical Association in 2006, he helped show that the subtype was more frequently seen in African-Americans.
In 2014, Perou continued his genetics research and led the largest genomic analysis of cancer tumors to date. The Cancer Genome Atlas study analyzed more than 3,500 tumors from 12 different tissue types.
Through that work, he and his collaborators found that some cancers should be completely reclassified based on their molecular characteristics. This new approach could shift how cancers are treated, and could also change the focus of drug development toward targeting groups of cancers with genomic similarities. The study said the findings could mean a “significant” number of patients could be considered for non-standard therapy.
Perou’s findings have also led to better diagnostic tools. In 2013, a laboratory testing kit that estimates the risk of breast cancer relapse in spite of anti-hormone treatment received approval from the U.S. Food and Drug Administration (FDA). This technology is based on a gene signature known as “PAM50” originally discovered by Perou. The tool, called ProsignaTM and manufactured by NanoString Technologies Inc., comes with a machine and kit so patients’ tumor samples do not have to be sent to a single laboratory for analysis. Understanding a breast cancer patient’s risk of recurrence is important in determining the next steps in ongoing treatment.