In a co-culture model with cancer and mesothelial cells and M2 macrophages, expression of P-selectin was regulated by M2 macrophages which secrete macrophage inflammatory pro1tein-1β (MIP-1β) that activates CCR5/PI3K signaling in mesothelial cells, resulting in upregulation of P-selectin on the mesothelial cell surface. The gene discussed is SELP; the disease is cancer.