PPARD and cancer: If PPARδ had similar activity in cancer cells as in muscle and stem cells, it could allow them to grow in metabolically stressful conditions.1, 7 We have shown that PPARδ mRNA and protein expression are upregulated when glycolysis is inhibited in leukemia cells.8 The experiments in this manuscript were designed to investigate the effect of PPARδ in harsh conditions such as found in breast cancer microenvironments.9