PGF and neoplasm: Early reports on the effect of cannabinoid compounds on tumour formation found a regressive effect based on anti-angiogenic effects through the downregulation of a number of proangiogenic parameters such as vascular endothelial growth factor (VEGF), placental growth factor (PlGF), angiopoietin-2 (Ang-2) [118, 119] and MMP-2 [119].