Consistent with a role for nSMase2 in the initiation of metastasis, intratumor injection of exosomes isolated from parental 4T1 cells to non-metastatic 4T1-nSMase2-KD cells after orthotopical inoculation into mammary fat pad significantly enhanced their metastatic colonization (Fig. 2A and supplemental Fig. 6A), whereas the growth of the inoculated 4T1-nSMase2-KD tumor cells was unaffected (supplemental Fig. 6B). Here, SMPD3 is linked to neoplasm.