Consistent with recently published gene expression microarray data [37], co-culture with HUVEC cells led to up-regulation of ID2 and or ID3 protein expression in CLL cells, an affect that was modulated by PEITC depletion of GSH or by direct addition of GSH or L-cysteine to an extent commensurate with rescue from cell death. Here, ID3 is linked to B-cell chronic lymphocytic leukemia.