We considered breast cancer SK-BR-3 and MCF-7 cells [3], lung cancer A-549 cells [28] as well as APL-derived and PML-RARα+NB4 blasts [29, 30] which synthesize measurable levels of S100A3 and RARα (Fig. 1b). The gene discussed is S100A3; the disease is acute promyelocytic leukemia.