Thus, a potential explanation for the formation of tumor islands in SHP2-silenced B16F10 tumors is that most tumor vessels are initially pruned, a phenomenon perhaps attributable to a localized deficiency of signals promoting endothelial cell survival (26), while other vessels undergo remodeling, providing a focal source of nutrients and oxygen and leading to clustering of proliferative cancer cells surrounding the remodeled vessels and to the death of cancer cells surrounding the dead/pruned vessels. This evidence concerns the gene PTPN11 and cancer.