Rather, because systemically injected lactadherin (which binds phosphatidylserine with very high affinity, v.g. Kd~0.08–4 nM) caused a marked blockade of SapC-DOPS-CVM targeting of GBM, we conclude that uptake and retention of SapC-DOPS by GBM cells in vivo is mediated by surface exposed phosphatidylserine. The gene discussed is MFGE8; the disease is glioblastoma.