Herein, we highlight several recent successes in which LC-MS-based proteomics has enabled the discovery of a classifier of five proteins (WAP four-disulfide core domain protein 2, WFDC2; prothymosin alpha, PTMA; nectin-4, PVRL4; fibrinogen alpha chain, FIBA; and nectin-2, PVRL2) for distinguishing between benign and malignant ovarian tumors [9], and a panel of six proteins (alpha-1-antichymotrypsin, AACT; trombospondin-4, TSP4; malate dehydrogenase mitochondrial, MDHM; calreticulin, CALR; protein LEG1 homolog, LEG1; and alpha-2-HS-glycoprotein, AHSG) for the detection of gliomas [10]. The gene discussed is CALR; the disease is glioma.