Transcriptomic analysis of KPCA.FSTKO and KPCA.FSTKO_hFSTL3-derived tumor revealed that endogenous mouse Fst and Fstl3 were predominantly expressed by cancer-associated mesothelial and fibroblast cells, which are major components of the stromal tumor microenvironment (Fig. 4D). Here, FSTL3 is linked to cancer.