The 16 cancer genes included in the assay are associated with proliferation (Ki67, STK15, Survivin, Cyclin B1, MYBL2), estrogen action (ER, PR, Bcl-2, SCUBE2), HER2/cERBB2 action (GRB7, HER2), invasion (Stromelysin 3, Cathepsin L2), or other functions (GSTM1, CD68 and BAG1). The gene discussed is ESR1; the disease is cancer.