VEGFA and Hand-foot syndrome: Because growing HFs produce and secrete vascular endothelial growth factor (VEGF) in the surrounding tissue to enhance vascularization providing nutrients [44,54,55,56], we assessed whether VEGF was differentially expressed in FPHL HFs vs healthy controls by measuring it by quantitative (immuno-)histomorphometry in the connective tissue sheath (CTS) surrounding the bulb, bulge, and sub-bulge regions, as well as in the DP (Figure S3A).