Pregnancy-associated alpha2 glycoprotein (α2PAG) synthesis by human breast cancer tissue and cultured cell lines

✍ Scribed by Edward J. Sarcione; Daniel Delluomo; Martin Zloty

• Publisher: John Wiley and Sons
• Year: 1983
• Tongue: French
• Weight: 517 KB
• Volume: 31
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.2910310203

✦ Synopsis

Elevated a,PAG serum levels are found in pregnant women and patients with diverse types of neoplasms including breast cancer. Primary human breast cancer tissue, MCF-7 and BT-20 human breast cancer cultured cell lines were shown to synthesize a,PAG in vitro. BT-20 breast cancer cells also released this pregnancy-associated protein. Synthesis was demonstrated by L-[ I4C)leucine incorporation into immunochemically isolated protein and confirmed by radioimmunodiffusion and radioimmunoelectrophoresis. These data (I) provide direct evidence for a,PAG synthesis by weltcharacterized human breast cancer cells per se;(2) strongly suggest that at least part of the a,ZPAG synthesis observed in primary human breast cancer tissue in vitro was due specifically to breast cancer cells rather than exclusively to monocytes/macrophages known to infiltrate neoplastic tissues and to produce this protein during pregnancy; and (3) are consistent with the conclusion that serum a,PAG is a definite breast cancer "marker protein" which originates from and reflects breast cancer status. On the basis of the aslociation of elevated serum a,PAG levels in breast cancer patients, its known immunosuppressive activity in vitro, and the direct evidence for a,PAG synthesis by human breast cancer cells per se, we postulate that this protein plays an important immunoregulatory role in vivo to prevent immune rejection and/or destruction of breast cancer cells. ' A preliminary report was presented at the 13th International Cancer Congress, Seattle, Washington, USA, September 8-15, 1982 (Proceedings, p. 171, Abstract No. 958).