ESR1 and osteosarcoma: In summary, combined treatment of the immature osteosarcoma cell line MG-63 with genistein and calcitriol results in: (1) a growth normalization of genistein induced proliferation, (2) overexpression of ERß, (3) reduction of extracellular acidification and respiration rates, (4) synergistically increased ethanolamine production, primarily initiated by a 3 – 4fold overexpression of the sphingosine-1-phosphate lyase.