Progesterone receptor isoforms expression pattern in human astrocytomas

Progesterone receptors (PR) have been detected in human astrocytomas; howev er, the expression pattern of PR isoforms in these brain tumors is unknown. Progesterone receptor isoforms expression was studied in 13 biopsies of as trocytomas (6 grade III, and 7 grade IV) from adult Mexican patients by usi ng reverse transcription-polymerase chain reaction and immunohistochemistry . Progesterone receptor expression was observed at mRNA and at protein leve ls in 66% and 83% of astrocytomas grade III, respectively, whereas 100% of astrocytomas grade IV expressed PR. Almost all PR mRNA content in astrocyto mas grades III and IV corresponded to PR-B. The number of immunoreactive ce lls expressing PR-B was higher than that expressing PR-A in 73% of the case s. Estrogen receptor-a protein was only observed in 33% of astrocytomas gra de III, whereas no astrocytomas grade IV expressed it. These data suggest t hat PR-B is the predominant isoform expressed in human astrocytomas grades III and IV, and that estrogen receptor-a is not expressed in astrocytomas g rade IV. (C) 2001 Elsevier Science Inc.