-- Question:What is the role of OncotypeDX and for what types of tumors is it used?
Answer: The thing that makes a cancer cell a cancer cell is its abnormal molecules -- particularly the DNA and the RNA, the instruction set that's in the cell. We now have various methods of looking at that instruction set and telling how those cells are going to behave with greater accuracy than we were able to do before, just looking at tumor size and some other characteristics.
One such test is the OncotypeDX, and that has been shown in a special category of breast cancer to help us treat the patient by knowing which tumors are best treated with a hormone therapy, in particular tamoxifen, or with cancer-killing drugs called chemotherapy -- in particular a combination called CMF.
OncotypeDX looks at various characteristics of the biochemistry of the tumor, the genes that are functional, and helps us make that distinction -- particularly in small tumors that are estrogen receptor-positive and that do not involve lymph nodes under the arm; node-negative, estrogen receptor-positive tumors, OncotypeDX has been proven to help us differentiate between tumors best treated with hormones alone or best treated with chemotherapy.