Single-cell RNA sequencing reveals spatial heterogeneity and immune evasion of circulating tumor cells

Circulating tumor cells（CTCs）, recognized as intermediaries between primary and distant lesions, are key to understanding the mechanisms of cancer metastasis. Because the dissemination of tumor cells in the circulatory system is a spatially and temporally dynamic process, CTCs can logically be assumed to be a population of cells displaying both spatial and temporal heterogeneity~1. Prior studies have revealed substantial temporal heterogeneity in CTC phenotypes during anti-cancer treatments 2,3 . However, current knowledge of CTCs is derived mostly from peripheral venous blood; thus, only a snapshot of the entire circulatory process has been determined, and much more remains to be understood.