PTPN11 and Osteochondroma: Taken together, these data suggest that the growth of osteochondroma in SHP2KOBglap;R26ZSG mice results from the developmental activation of the Bglap promoter and the inactivation of SHP2 in chondroid but not osteoblastic cells and that this pathologic process is relatively slow, which is likely due to the low activity of Bglap-Cre in chondroid cells so that it cannot mediate efficient deletion of SHP2-floxed alleles.