Methods are provided herein for identifying whether a cancer patient, for example a colorectal cancer patient, will be responsive to treatment with a therapeutic strategy comprising administration of the FOLFOX regimen (5-fluorouracil, leucovorin, and oxaliplatin). Specified TYMP and UCK2 fragment peptides are precisely detected and quantitated by SRM-mass spectrometry directly in tumor cells, for example colorectal cancer tumor cells, that are collected from tumor tissue obtained from a cancer patient and compared to reference levels in order to determine if the cancer patients will positively respond to treatment with the combination treatment of FOLFOX (5-fluorouracil, leucovorin, and oxaliplatin).
