SMPD3 and breast cancer: We also confirmed similar results using an orthotopic model of MDA-MB-231-D3H2LN cells, which are human breast cancer cells with a high metastatic ability, overexpressing or inhibiting nSMase2 (Fig. 1E), which suggests that the alteration in expression level of nSMase2 leads to the change in metastatic ability of cancer cells.