PTGS2 and neoplasm: The cumulative results from these studies (Figs 1, 2, 3, 4, 5) therefore suggested a cell damage‐induced programming pathway for this Sca‐1+/metastatic phenotype with steps including: Tumor cell injury > Cox2 > PGE2 > PGE2‐R > metastatic Sca‐1+ cells.