“…OGF is a constitutively expressed native opioid that is autocrine produced and secreted to inhibit the growth of both normal cells McLaughlin, 1987, 1991;Hauser et al, 1990;Stiene-Martin and Hauser, 1990;Hauser and Stiene-Martin, 1991;Isayama et al, 1991;Villiger and Lotz, 1992;Zagon et al, 1994Zagon et al, , 1995aZagon et al, ,b, 1996aZagon et al, , 1997aZagon et al, ,b, 1998Zagon et al, , 1999bZagon et al, , 2000bMcLaughlin, 1996;Vertes et al, 1996;McLaughlin and Wu, 1998;Blebea et al, 2000;Wilson et al, 2000;Kornyei et al, 2003;Robertson and Andrew, 2003;Malendowicz et al, 2005) and cancer cells (Zagon et al, 1996c;Cheng et al, 2007Cheng et al, , 2008. The action of OGF is tonic, stereospecific, reversible, noncytotoxic, and nonapoptotic inducing, is not associated with differentiative, migratory, invasive, or adhesive processes, is independent of serum, anchorage-independent and occurs at physiologically relevant concentrations (Zagon et al, , 2007a, 2004.…”