Vickman RE, Broman MM, Lanman NA, et al. - Single-cell RNA-seq of primary human prostate carcinoma-associated fibroblasts (CAF) followed by unsupervised clustering was used to create cell clusters on the basis of differentially expressed (DE) gene profiles in order to ascertain whether unique sub-populations of human prostate CAF could be recognized and functionally identified. The clustering of 3,321 CAF allowed for visualization of six subpopulations, showing heterogeneity within CAF. On the basis of DE gene expression, CAF clustering encouraged the concept that clusters have novel functions within the tumor microenvironment, involving a role in immune/inflammatory cell recruitment. Data suggest that C-Cmotif chemokine ligand 2 exhibited by CAF may be included in the involvement of inflammatory cells, however, it may also directly control the growth of the tumor.