Frequency of Expression of Prostate-Specific Antigen mRNA in Lung Tumors

Abstract

The presence of prostate-specific antigen (PSA) protein and messenger RNA (mRNA) was studied in 52 primary lung tumor tissues. The PSA protein was detected more frequently and at higher levels in lung tumor extracts from men. The levels of PSA protein in tumor extracts correlated with preoperative and postoperative serum PSA levels, suggesting a possible contamination of the tumor extracts with PSA from residual blood in the tumor vasculature. The PSA mRNA was detected by reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot hybridization in 24 (68%) of 35 tumors from men, in 9 (53%) of 17 tumors from women, and in 5 (71%) of 7 adjacent normal lung tissue specimens. The levels of PSA protein did not associate with patient age, the tumor stage, grade, or histologic type, or the nodal status. Similarly, PSA mRNA was not associated with any clinicopathologic variables, but squamous cell carcinomas, especially in men, were more frequently positive. A by-product of the RT-PCR procedure was cloned and sequenced and found to be a 450-base pair sequence not previously deposited in the data bank. We conclude that PSA mRNA and protein frequently can be detected in lung tumors and normal tissues from men and women but at levels much lower than those seen in breast carcinomas in women. The significance of the new 450-base pair sequence remains to be determined.

Circulating testosterone and prostate-specific antigen in nipple aspirate fluid and tissue are associated with breast cancer.

“…Breast PSA is also under hormonal control (22,23). PSA production is inducible in cultured T47D breast cancer cells by the addition of steroid hormones, including androgens and progestins, to the culture media (23)(24)(25).…”

A 6-kb Promoter Fragment Mimics in Transgenic Mice the Prostate-Specific and Androgen-Regulated Expression of the Endogenous Prostate-Specific Antigen Gene in Humans

“…The specific expression of the transgene in the mouse lateral prostate is in agreement with the structural homology between the human prostate and the mouse lateral prostate, and the mouse kallikrein expression in the lateral prostate. The variable level of PSA expression in human breast cancer (23) and the activity of the 6-kb PSA promoter in transiently transfected T47D human mammary tumor cells (14) could not be confirmed in normal breast tissue of female PSA-61-LACH transgenic mice (data not shown).…”

Reconnoitring the Status of Prostate Specific Antigen and its Role in Women

“…Bodey et al [27] detected PSA immunocytochemically in primary and metastatic melanomas. Strengthening the fact that PSA is an ubiquitous molecule and not restricted to prostate gland alone was the observations of Zarghami et al [28] who detected PSA in lung tumours and normal lung tissue. Similarly, Clements et al [29] in their study registered the presence of PSA mRNA in some pituitary tumours by RT-PCR.…”