PTPRC and atherosclerosis: Other objectives will be to determine whether the vasculogenic properties of these cells are adaptive or maladaptive in diseases such as atherosclerosis; whether similar cells are present in human arteries, where Sca-1 cannot be used as a candidate marker for their identification; and whether there are corresponding populations of CD45+ progenitors residing around the microvasculature of other tissues, that might participate in vasculogenic responses to wound healing, ischaemia and cancer.