CXCL12 and aneurysmal bone cyst: However, restricting within ABC-DLBCL, CD5+ compared to CD5− patients had similar levels of CXCR4 but had a higher incidence of BM involvement (34.5% vs. 7.2%, P < .0001, Table 2), suggesting that CXCR4/CXCL12 axis was not sufficient to explain for the BM involvement.