Control experiments showed that wild-type donor to wild-type recipient transplantation did not cause any liver phenotype (Fig. 8c, d); and that knockout donor to knockout recipient transplantation generated liver hemangioma phenotype with severity indistinguishable from the HOXB7-Cre; Vhlhfl/fl mice (Fig. 8c, e). The gene discussed is HOXB7; the disease is liver hemangioma.