FGF2 and skin basal cell carcinoma: Using an in vitro noncontact co-culture system, Tjiu and colleagues demonstrated that both M2-polarized THP-1 and monocyte-derived M2 macrophages promote extracellular matrix degradation, invasiveness and angiogenesis of BCC cells by inducing COX2-dependent MMP-9, VEGF-A and basic fibroblast growth factor (bFGF) expression, via the p38 MAPK/NF-κB cascade [171].