CD8A and cancer: Furthermore, IL-33 produced by stromal cancer-associated fibroblasts (CAFs) exerts its paracrine effects on tumor invasiveness and metastasis via EMT, while distinct type-1 (e.g., cytotoxic CD8+ T cells, and NK cells) and type-2 immune cell components (e.g., TAM, MDSC, and Treg) determine their anti- and pro-tumor activities, respectively, through paracrine modulation of either cancer cell-derived or stromal IL-33 (see more details below).