In the future, use of a conditional Pdgfrb-iCreERT2 mouse (Claxton et al., 2008) that allows specific deletion of Trp53 in the adult, in which Pdgfrb expression is restricted to pericytes, will allow further evaluation of the role of distinct mesenchymal cell lineages to the development of different sarcoma subtypes. The gene discussed is TP53; the disease is sarcoma.