SELPLG and Miyoshi myopathy: In addition, it was demonstrated previously that PSGL-1 and selectins are involved in macrophage-mediated drug resistance in MM; by blocking PSGL-1 in MM cells with antibody or by silencing PSGL-1 with shRNA using lentiviral vector, MM cells were resensitized to melphalan when cocultured with macrophages, which was driven by Erk1/2 pathway activation and c-myc upregulation [23].