Mirkeshavarz et al. (2017) found that CAFs can secrete interleukin-6 (IL-6) and VEGF to induce angiogenesis in oral cancer, and that IL-6 can induce the secretion of VEGF in CAF cell lines. CAF can also release active growth factors from the ECM by expressing MMPs, which indirectly promotes angiogenesis (Najafi et al., 2019b) and serves as one of the sources of MMP9 (Boire et al., 2005) and MMP13 (Vosseler et al., 2009). Both these substances have been shown to release VEGF from the ECM to increase angiogenesis in tumors (Lederle et al., 2010). This evidence concerns the gene IL6 and lip and oral cavity carcinoma.