Yu H, Diamandis E P, Monne M, Croce C M
Department of Clinical Biochemistry, Toronto Hospital, Ontario, Canada.
J Biol Chem. 1995 Mar 24;270(12):6615-8. doi: 10.1074/jbc.270.12.6615.
Prostate-specific antigen (PSA) is widely used as a tumor marker of prostatic adenocarcinoma. We recently found that 30% of breast tumors produce PSA and that PSA is a favorable prognostic marker in female breast cancer. We measured immunoreactive PSA in cytosolic extracts of normal breast tissue from eight women receiving no medication and one woman who was receiving no medication and one woman who was receiving the progestin-containing oral contraceptive Brevicon. None of the eight cytosolic extracts of normal breast tissue contained appreciable amounts of immunoreactive PSA. However, left and right breast tissues from the woman receiving Brevicon contained high levels of PSA. This immunoreactive species was shown to have a molecular weight identical to that of seminal PSA. Furthermore, reverse transcription of RNA and polymerase chain reaction amplification produced a 571-base pair cDNA that hybridized to a labeled cDNA PSA probe. Upon sequencing, the cDNA polymerase chain reaction product was found to have 100% homology with cDNA from prostatic tissue. PSA production by breast carcinoma cell lines was achieved after in vitro stimulation with norethindrone and ethinylestradiol. Our data suggest that PSA can no longer be regarded as a specific prostatic protein because it is produced by breast tumors with good prognosis and by normal breast tissue after steroid hormone stimulation.
前列腺特异性抗原（PSA）被广泛用作前列腺腺癌的肿瘤标志物。我们最近发现，30%的乳腺肿瘤会产生PSA，并且PSA在女性乳腺癌中是一个良好的预后标志物。我们检测了8名未接受药物治疗的女性以及1名未接受药物治疗且正在服用含孕激素口服避孕药Brevicon的女性的正常乳腺组织胞质提取物中的免疫反应性PSA。8份正常乳腺组织的胞质提取物中均未含有可检测到的免疫反应性PSA。然而，服用Brevicon的女性的左右乳腺组织中含有高水平的PSA。这种免疫反应性物质的分子量与精浆PSA相同。此外，RNA逆转录和聚合酶链反应扩增产生了一个571个碱基对的cDNA，它与标记的cDNA PSA探针杂交。测序后发现，该cDNA聚合酶链反应产物与前列腺组织的cDNA具有100%的同源性。用炔诺酮和炔雌醇体外刺激乳腺癌细胞系后可产生PSA。我们的数据表明，PSA不能再被视为一种特异性的前列腺蛋白，因为它由预后良好的乳腺肿瘤以及类固醇激素刺激后的正常乳腺组织产生。
