Earlier, we reported that trametinib treatment suppresses ERK1/2 phosphorylation and the expression of MEK/ERK-responding genes in ovarian cancer xenografts [18]; it is possible that the efficiency of MEK/ERK-targeting therapy in ovarian and other cancers may be monitored via the detection of COMS genes (or other optimized transcriptional signatures) in fine-needle aspiration biopsy or CTC samples. Here, MAPK3 is linked to ovarian carcinoma.