Expression levels of prominent angiogenesis-related genes such as VEGFA, FGF2, and angiopoietin 1 & 2 (ANGPT1/2) were significantly upregulated in ETV2-transduced hearts (Fig. 2b), while cardiac fibrosis markers, such as collagen type 1 (COL1), collagen type 3 (COL3), and matrix metalloprotease 2/9 (MMP2/9), were substantially downregulated. Here, MMP2 is linked to fibrosis.