To assess a possible role for the hUC-MSCs in inducing Notch signaling in the Jurkat T-ALL cells, the expression of Notch ligands Jagged1, DLL1 and DLL4 were examined in the hUC-MSCs by PCR using gene-specific primers, with β-actin as an internal control (Table I). Here, DLL4 is linked to acute lymphoblastic leukemia.