RT Journal Article SR Electronic T1 Reduction of Tumorigenicity by Placental Extracts JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 1153 OP 1161 VO 32 IS 4 A1 ANNETTE M. MARLEAU A1 GREG MCDONALD A1 JAMES KOROPATNICK A1 CHIEN-SHING CHEN A1 DAVID KOOS YR 2012 UL http://ar.iiarjournals.org/content/32/4/1153.abstract AB The influence of adult stem cells on tumor growth is paradoxical. On one hand, angiogenic factors secreted by stem cells are known to be essential for tumor vascularization. On the other hand, stem cell-derived factors can reportedly induce tumor differentiation or direct death of tumor cells. Both the placenta and umbilical cord are rich sources of stem cells with immune modulatory and tissue-healing properties; however, the effects of placental components on cancer cells have not been fully defined. Here we demonstrate that extracts of placental lysates reduce the malignancy of a variety of human tumor cell lines in a species-unrestricted manner. Using a standard model of leukemia cell differentiation, we demonstrated that addition of placental extracts to tumor cells, or co-culture of tumor cells with the CD34+ cells from umbilical cord blood, induced tumor cell differentiation. Inhibition of tumor growth and metastasis in vivo was also observed following administration of placental extracts. These data support the concept of non-toxic biological therapy of cancer using stem cell derivatives, possibly through the induction of tumor cell differentiation.