Fig. 1: Schematic workflow of circulating tumor cell (CTC) subgrouping and colorectal cancer metastasis prediction using home-built single-cell quantitative mass spectrometry platform.

First, two pairs of colorectal cell lines with differential metastatic potential were screened using mass spectrometry-based untargeted metabolomics, and metabolites with differential abundance correlating with cancer metastatic risk were identified. Then, CTCs were isolated from colorectal cancer patients. Cellular content was extracted from single CTCs, and target metabolites were analyzed using single-cell quantitative mass spectrometry. A molecular typing system of colorectal cancer was developed to identify metabolic fingerprint correlated with metastasis and to construct a CTC subgrouping approach to predict the incidence of metastasis in colorectal cancer patients at the single-cell metabolite level. Some graphical elements were created with BioRender.com (accessed on 24 March 2023). UPLC-HRMS ultra-performance liquid chromatography-tandem high-resolution mass spectrometry.