Although blocking 90% of CXCR7 markedly decreases migration for the CXCL12-α-like parameters, it has much less of an effect in modulating migration for ligand with higher affinities to the migration surface and to CXCR4, further highlighting the potential importance of understanding the role of high affinity ligands like CXCL12-γ within the tumor environment. The gene discussed is CXCR4; the disease is neoplasm.