Oncotype DX breast cancer assay (ON-koh-tipe … brest KAN-ser A-say)
A laboratory test that is used to help predict whether breast cancer will spread to other parts of the body or come back. The test looks at the activity of 21 different genes in breast cancer tissue of women who have early-stage invasive breast cancer that is estrogen receptor positive and has not spread to the lymph nodes or has spread to 3 or fewer lymph nodes. If the test shows that there is a high risk that the cancer will spread or come back, treatment with anticancer drugs may be needed. Also called 21-gene signature.