VEGFA and hypervitaminosis A: Notably, megakaryocytosis and fibrosis and several other pathological bone changes, such as bone thinning and weakening, increased number of periosteal osteoclasts, increased expression of osteoblast marker genes and increased osteoprotegerin expression, that have been described in conjunction with hypervitaminosis A are also features of Vegfa overexpression and myelofibrosis (Kneissel et al., 2005; Lind et al., 2011; Lind et al., 2012; Johansson et al., 2002; Forouhar et al., 1984; Varani et al., 2003; Tefferi, 2005).