Data from a large-scale microarray experiment (M Gallagher, unpublished data) involving embryonal carcinoma cancer stem cells (NTera2 and 2102Ep) was interrogated for differential TLR4-signalling gene expression, which indicated that MyD88 expression was high in undifferentiated NTera2 cells and decreased rapidly upon differentiation in retinoic acid (RA). The gene discussed is TLR4; the disease is embryonal carcinoma.