TLR9 and acute lymphoblastic leukemia: BAFF-R can be positively regulated by B-cell receptor stimulation and Toll-like receptor (TLR)-associated signaling, and negatively regulated by TNFR-associated factor-3; TLR signals also upregulate TACI.[44], [45], [46] Although TLR mRNAs (TLR1 to -7) were detected in leukemia lines and TLR9 protein in primary B-ALL, and B-ALL are responsive to TLR stimulation by CpG oligodeoxynucleotides,[47], [48] there is no evidence supporting a role for TLR signals within the leukemic BM, or their effects in B-ALL biology.