The role of prostate-specific antigen as part of the diagnostic triad and as a guide when to perform a biopsy.

The authors reviewed the results and relationship of prebiopsy prostate-specific antigen (PSA) assay, digital rectal examination (DRE), and transrectal ultrasound (TRUS) in 124 consecutive patients who underwent a prostate biopsy because of abnormal results of either DRE or TRUS. Results of the three tests (PSA, DRE, and TRUS) showed abnormalities in 54%, 75%, and 84.6% of patients, respectively; biopsy results were positive for cancer in 45.2%. Cancer detection rate increased as the PSA value increased from less than or equal to 4 ng/ml (17.5%) to more than 4 ng/ml (68.7%) to more than 20 ng/ml (83.3%), and as the number of positive tests increased (6.9% for one, 32.7% for two, and 82.6% for three). The PSA assay was the most important parameter of the diagnostic triad. These results suggested that regardless of DRE and TRUS findings, PSA less than or equal to 4 ng/ml confers a low prostate cancer risk, PSA more than 4 ng/ml but less than or equal to 10 ng/ml confers an intermediate prostate cancer risk, and PSA more than 10 ng/ml confers a high prostate cancer risk. Regardless of other findings, all patients with a PSA value more than 10 ng/ml require biopsy because of the high likelihood of cancer. All patients with abnormal DRE or TRUS results still require biopsy despite a low index of suspicion of prostate cancer when the PSA value is less than or equal to 4 ng/ml.

Monoclonal prostate-specific antigen in untreated prostate cancer. Relationship to clinical stage and grade.

The authors evaluated 440 men with clinically staged and untreated prostate cancer with a monoclonal prostate-specific antigen (PSA) assay. The serum PSA value correlated significantly with both the stage and grade of disease (P less than 0.00005). The relationships between PSA and consecutive Stages A, B, C, and D2 (alpha = 0.15) and between progressive Gleason's scores 2 to 4, 5 to 7, and 8 to 10 (alpha = 0.15) were statistically significant. Also statistically significant was the correlation between serum PSA level and intracapsular versus extracapsular disease (P less than 0.00005), although no one value can be used to differentiate reliably between patients in these two categories. The probability of clinically detectable metastasis (Stage D2) is 85% if the serum PSA level is greater than 30; however, 12% of patients without clinical evidence of metastases (Stages A, B, and C) have such a serum PSA value. Despite the statistically significant association between PSA and tumor differentiation and volume as reflected by tumor grade and clinical stage, this marker cannot be used to determine either for an individual patient.

Fibroblast-mediated acceleration of human epithelial tumor growth in vivo.

Transformed fibroblasts coinoculated with epithelial cells accelerated the growth and shortened the latency period of human epithelial tumors in athymic mice. Addition of NbF-1 fibroblasts caused epithelial tumors to grow from five marginally tumorigenic or "nontumorigenic" (nontumor-forming) human tumor cell lines or strains: PC-3 (prostate), WH (bladder), MDA-436 (breast), and cells derived from the ascites fluids of patients with metastatic renal pelvic or prostate cancers. Evidence for the human and epithelial nature of these experimental tumors was provided by histologic, immunohistochemical, Southern and dot-blot hybridization, and cytogenetic analyses. Transformed fibroblasts induced predominantly carcinosarcomas, whereas nontumorigenic fibroblasts (NIH 3T3) and lethally irradiated transformed fibroblasts induced exclusively carcinomas. The fibroblast-epithelial interaction appears to occur bidirectionally and does not result from cell fusion. Because coculture experiments in vitro did not demonstrate an increased cell proliferation, it appears that undefined host factors can influence tumor growth. This tumor model may be useful in drug-screening programs and in mechanistic studies of factors regulating human tumor growth and progression.

The epithelial origin of a stromal cell population in adenocarcinoma of the rat prostate.

Dunning R3327-H rat prostate adenocarcinoma cells, when grown in syngeneic (Copenhagen) rats or nude mice, produce tumors with prominent hypercellular stroma. The authors have previously demonstrated the presence of anomalous steroid-sensitive cells in both the epithelium and stromal compartments of this model system. In order to better understand the histogenesis of these cells, the authors studied samples of the tumor which were radiolabeled overnight with tritiated dihydrotestosterone (3H-DHT). Frozen sections of the tissues were thaw-mounted onto autoradiographic emulsion-coated slides to permit silver grain identification in association with nuclei of androgen-sensitive cells. Surprisingly, numerous silver grains were found to be associated with nuclei of large cells within the stroma. Therefore, these cells were termed "epithelioid" pending confirmation of their origin. To further define these cells and their relationship to the surrounding matrix, autoradiograms have now been examined immunohistochemically with antibodies directed against the basement membrane glycoprotein, laminin, as well as antibodies specific for intermediate cytoskeletal filaments. Following identification of acinar basement membranes, epithelioid cells were identifiable both in the stroma and in the acinar epithelial cell layer. Histochemical staining with acid phosphatase, a marker for prostatic epithelium, was performed and shown to be present in acinar epithelial cells as well as in epithelioid cells. Additionally, fluorescence-activated cell sorting was employed to characterize the DNA content of cell types within the H tumor. Epithelioid cells were found to be in highest concentration in an aneuploid peak with a ploidy of approximately 6N. The autoradiographic, immunohistochemical, cytometric, and ultramicroscopic studies suggest that 1) epithelioid cells are epithelial derived stromal cells; 2) these epithelioid cells arise by pathologic division of aneuploid neoplastic precursor cells of approximately 3N ploidy, which are found within the prostatic epithelium; and 3) the resulting 6N cells degrade the basement membrane locally, invade the stroma, and populate it. Here, they can be distinguished from fibroblasts by their size, acid phosphatase activity, and hormone receptor content. Thus, the term "epithelioid" is inappropriate; and these cells should be regarded simply as large neoplastic epithelial (LNE) cells. The presence of this cell type suggests that this tumor subline represents a useful naturally occurring model for the study of the initial stages of neoplastic transformation.

Analysis of changes in rat prostate carcinoma following hormone deprivation.

The R3327-H model of prostatic adenocarcinoma was employed for the study of the cellular changes that occur during induction, regression, and recurrence of prostate cancer after endocrine therapy. The present study was designed to compare the glandular and stromal elements of the relapse phase with the histologically distinct early and intermediate phases of tumor progression. Morphometric analysis revealed significant differences between all three groups in the percentages of total tumor occupied by the epithelial component. At all three time periods, high-power inspection of autoradiograms prepared after incubation of the tissues with radioactive dihydrotestosterone revealed large cells in the stroma, especially in the intermediate phase. Immunohistochemistry further revealed evidence of invasion across the prostatic acinar basement membranes by similar cells. These studies lead the authors to postulate a mechanism by which hormone-independent cells in the epithelium repopulate the stroma, causing a recapitulation of the original morphology of the tumor in the postremission period. They propose that prostate tumor response to estrogen therapy can be operationally defined in three phases: involution, rebound, and relapse. They infer that further knowledge of the timing of these phases may permit early selective use of specific therapeutic strategies which will be able to balance the clinical risk with the known behavior of the neoplasm during progression of the disease.

Differential retention of rhodamine 123 by avian sarcoma virus-induced glioma and normal brain tissue of the rat in vivo.

The time course of uptake, retention and clearance of the cationic lipophilic dye, rhodamine 123 (Rh123), within the central nervous system was qualitatively evaluated in rats. Weanling rats were injected intracerebrally with avian sarcoma virus, which induced malignant gliomas in situ before injection of Rh123. Comparison was made of the amount of fluorescence of Rh123 within the normal cerebral cortex, myelinated tracts of the brain, meninges, choroid plexus, and neoplastic foci at 1, 4, 8, 12 and 24 hours after intravenous injection. Fluorescence microscopy was utilized to identify tissues containing the dye. Normal neuropil did not contain Rh123 at any of the time periods studied. Gliomas retained the dye at 1, 4, 8 and 12 hours, with increasing uniformity of distribution and decreasing intensity of fluorescence over this time period. Fluorescence was not detected at 24 hours within the neoplastic tissues, but was evident at all time periods studied within the choroid plexus. The specific retention of Rh123 by malignant glioma and by the choroid plexus in vivo suggests that Rh123 may be useful for photochemotherapeutic treatment of brain neoplasms and disorders of the choroid plexus.

High-performance liquid chromatographic quantitation of rhodamines 123 and 110 from tissues and cultured cells.

Rhodamine 123 is a fluorescent vital dye which has potential for therapeutic use in cancer treatment. The dye concentrates in mitochondria of normal and neoplastic cells but accumulates in and is toxic to neoplastic cells. When dye-treated cells are irradiated with blue laser light at 514 nm, mitochondrial injury or cell death results. Rhodamine concentration in cultured cells and tumor tissue was quantitated to correlate cell or tumor death with drug dose. A reversed-phase separation of rhodamine 123 was accomplished using a gradient of 0.05 M phosphate buffer pH 2.85 (mobile phase A) and acetonitrile (mobile phase B), 10-80% B in 15 min with a DuPont Golden Series C8 column. Effluent was monitored with a fluorescence detector at 295 nm excitation and 520 nm emission. Stock rhodamine 123 contained approximately 6-8% of rhodamine 110, the parent compound, which eluted at 9.8 min whereas rhodamine 123 eluted at 11.7 min. Structural verification of both compounds by field desorption mass spectrometry was performed. This is the first report of the chemical separation and quantitation of rhodamine 123 from cultured tumor cells or tumor tissue.

Photodynamic therapy of prostate cancer: an in vitro study.

The photo-induced toxicity of hematoporphyrin derivative on Dunning R3327 rat prostate cancer cells was studied. Dunning R3327 cells in culture were incubated for two hours in hematoporphyrin derivative and then exposed to red light at 630 nanometers wavelength from an argon pumped dye laser. Cell survival was measured for varying laser power densities, variable concentrations of hematoporphyrin derivative and variable light exposure times. AT1 cells not incubated with hematoporphyrin derivative were directly killed by laser light exposure at power densities greater than 500 mw./cm.2, probably due to hyperthermia. Cells that retained hematoporphyrin derivative were effectively killed using non-thermal levels of red light exposure due to a photochemical effect. Decreasing cell survival of cells that retained hematoporphyrin was related to increasing time of exposure to red light. This form of therapy may be applicable to the treatment of locally invasive prostatic carcinoma in man.