These adipocyte stem cells previously defined by the expression of PDGFR, a marker of mesenchymal cell populations, fit with the accumulating knowledge acquired in recent years about subsets of cancer stem cells (CSCs) expressing CD26 that have been implicated in metastases of many cancers [18,19,20], including hematological (leukemic stem cells—LSCs, reviewed in [21]). This evidence concerns the gene PDGFRB and cancer.