Update information. Most of the carcinogenesis of colorectal cancer (CRC) follows the normal-adenoma-carcinoma (N-A-C) sequence. We aimed to identify the key proteins in the N-A-C sequence and describe the proteomic pattern of tubular adenoma, tubulovillous adenoma and high-grade neoplasia. This study used high-resolution liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), in combination with quantitative 5-plex tandem mass tag labeling, to profile protein changes in normal epithelium, tubular adenoma, tubulovillous adenoma, high-grade neoplasia, cancer tissues in colorectum.