M-S extraction method can be generically used for immortalized human cell lines. Molecular features from positive and negative TOF-MS conditions were identified using MarkerLynx software (Waters Corp.). MCF-7 and MDA-MB-231, Human breast adenocarcinoma; LNCaP, androgen-sensitive human prostate carcinoma; DU-145, brain metastasis of human prostate carcinoma; PC-3, bone metastasis of human prostate adenocarcinoma; HCT116, human colorectal carcinoma; COLO357, human pancreatic adenosquamous carcinoma; PANC-1, human carcinoma of the exocrine pancreas.