However, our model predicts that increasing the secretion of PF4 in tumor tissue can lead to two counterintuitive results: an increase in interstitial FGF2 and VEGF levels (see Platelet Factor 4 Secretion Can Increase the Levels of Unbound Pro-angiogenic Factors in Tumor in Section “Results”) and greater formation of pro-angiogenic signaling complexes, particularly in the VEGF signaling pathway (see VEGF Signaling Shows a Biphasic Response to the HSPG Level and PF4 Secretion Rate in Section “Results”). This evidence concerns the gene PF4 and neoplasm.