CCL2 and precursor B-cell acute lymphoblastic leukemia: sSig15 in pediatric patients with B-ALL was found to negatively correlate with antileukemia cytokines such as IL12 and positively correlate with immunosuppressive factors such as MCP-1/CCL2 and IL6, suggesting sSig15 is one component of a complex immunosuppressive local and systemic microenvironment in B-ALL.