CXCL12 and cancer: In many solid cancers, expression of CXCL12 by cancer-associated fibroblasts (CAFs) leads to the exclusion of T cells, and we also found that fibroblastic foci were the main source of CXCL12 expression (Figure 6J), suggesting that this chemokine may function to exclude immune cells from the fibrotic niche in lung fibrosis.