Cytokeratin 5/8 and Desmin antibodies did not stain tumor sections of β-catΔ/Δ mESC lines, in contrast to β-catfl/fl and res-β-catΔ/Δ teratomas in which approximately 10–40% of the cells were positively stained (Figure 3B). The gene discussed is DES; the disease is neoplasm.