Robert L. Vessella

The Value of Serum Prostate Specific Antigen Determinations Before and after Radical Prostatectomy

We evaluated serum prostate specific antigen before and after radical prostatectomy. In 100 consecutive patients who underwent radical prostatectomy, preoperative prostate specific antigen levels tended to increase with the increasing severity of pathological stage. However, even at levels of greater than 10 ng. per ml. the positive and negative predictive values (78 and 61 per cent, respectively) of prostate specific antigen to predict extracapsular disease were not sufficient to make this test useful alone for staging. In theory, after radical prostatectomy prostate specific antigen should be zero if no remaining prostatic tissue is present. Tests of precision and analytical sensitivity in our laboratory using a commercial prostate specific antigen assay revealed that a value of 0.4 ng. per ml. or more is different from zero at a greater than 95 per cent confidence level. With this guideline we evaluated the meaning of prostate specific antigen levels 3 to 6 months after radical prostatectomy in 59 men. Among men whose prostate specific antigen level was less than 0.4 ng. per ml. only 9 per cent demonstrated recurrence as evidenced by the development of positive bone scan or progressively elevated prostate specific antigen levels within 6 to 50 months. Alternatively, in men whose 3 to 6-month prostate specific antigen level was 0.4 ng per ml. or more there was evidence of recurrence in 100 per cent within 6 to 49 months (p less than 0.0001). Progressively elevated (more than 0.4 ng. per ml.) prostate specific antigen levels preceded recurrence from 12 to 43 months in all 6 patients who had positive bone scans, while increasing prostate specific antigen levels since radical prostatectomy have continued from 9 to 65 months in the 11 patients who have no radiological evidence of recurrent disease to date. Prostatic acid phosphatase serum values after radical prostatectomy were not useful to predict persistent disease. Prostate specific antigen values 3 to 6 months after radical prostatectomy are a sensitive indicator of persistent disease after radical prostatectomy and often precede other evidence of this occurrence by many years. This fact may alter concepts about surgical results, and possibly shorten and sharpen clinical studies involving adjuvant therapy after radical prostatectomy.

Prostatic Specific Antigen and Prostatic Acid Phosphatase in the Monitoring and Staging of Patients with Prostatic Cancer

Serum prostatic specific antigen and prostatic acid phosphatase levels were measured retrospectively and evaluated in 357 men with benign prostatic hypertrophy and in 209 men with various stages of prostatic carcinoma. Although prostatic specific antigen values were elevated in 21 per cent of the patients with benign prostatic hypertrophy, the elevations usually were low and did not interfere with clinical interpretation. Prostatic specific antigen was elevated in 98 per cent of 86 men with active stage D2 disease; in 22 per cent of the men prostatic specific antigen was the only elevated marker. In contrast, prostatic acid phosphatase was the only elevated marker in 1 per cent of the patients with stage D2 disease and neither marker was elevated in 2 per cent. Among 74 patients in whom prostatic specific antigen and prostatic acid phosphatase determinations were made before radical prostatectomy, prostatic specific antigen was elevated substantially (greater than 10 ng. per ml.) in 59 per cent (26 of 44) with extracapsular disease and in only 7 per cent (2 of 30) without extracapsular disease. More importantly, of those 28 patients with substantially elevated prostatic specific antigen levels 26 (93 per cent) had extracapsular disease. Serial serum measurements showed that prostatic specific antigen either reflected or predicted clinical status in more than 97 per cent of the patients. We conclude that prostatic specific antigen is an excellent serum tumor marker for monitoring patients with prostatic carcinoma and that it surpasses prostatic acid phosphatase in this regard. Prostatic specific antigen also may be useful in staging prostatic carcinoma and it may change our attitudes significantly about the therapeutic responses to this cancer.

The Effect of Radiation Therapy after Radical Prostatectomy in Patients with Elevated Prostate Specific Antigen Levels

We analyzed the effects of pelvic radiation therapy given to patients who had an elevated prostate specific antigen level after radical prostatectomy. Among men who previously received adjuvant radiation therapy and had appropriately stored serum 15 had elevated prostate specific antigen levels after radical prostatectomy but before radiation therapy. After radiation therapy the prostate specific antigen level decreased by more than 50% in 80% and to female levels in 53% of the patients. We also prospectively treated 29 men who had increasing levels of prostate specific antigen 9 to 95 months after radical prostatectomy but who were otherwise without evidence of disease by the usual criteria. However, 19 of the patients had local disease as evidenced by random needle biopsy of the urethrovesical anastomosis. Complications of radiation therapy were minimal and maximal prostate specific antigen decrease occurred by 6 months after treatment. In 82% of the patients prostate specific antigen levels decreased by more than 50% and in 43% they decreased to female levels. Female levels were achieved after radiation therapy given many years postoperatively even in stage D1 cancer patients but some of the patients subsequently had increasing prostate specific antigen levels. These data suggest that local-regional disease may be the only site of disease persistence after radical prostatectomy in some of the patients who subsequently have distant metastasis. We conclude that radiation therapy after radical prostatectomy can cause elevated prostate specific antigen to decrease to undetectable levels in many patients but the durability and ultimate therapeutic value of this effect are unknown.

A, B, H antigens in transitional cell tumors of the urinary bladder: correlation with the clinical course.

The A, B, H blood group antigens can be detected in normal transitional epithelium of the urinary bladder by the red cell adherence (RCA) test. We examined the possibility that the reactivity for these antigens is lost or decreased in transitional cell carcinomas and that such a change may reflect the future evolution of these tumors. We studied several bladder biopsies from 60 patients who presented with noninvasive transitional cell carcinomas and were followed for at least 5 years or until muscle invasion was histologically demonstrated. Eighty‐one percent of patients whose tumors were RCA positive in the initial biopsy did not subsequently develop invasive tumors and 27% of these patients had no recurrences. All 34 patients whose tumors were negative in the initial biopsy experienced recurrences and 62% of them developed invasive lesions. In 81% of patients, the recurrent tumors retained the same pattern of RCA reactivity for blood group antigens on serial biopsies. These results suggest that the presence of readily detectable A, B, H antigens correlates with a favorable prognosis whereas their absence denotes an aggressive potential.

A human embryonal—yolk sac carcinoma model system in athymic mice

Two new human cell lines (1411H and 1411HRQmet) have been established from a patient with metastatic testicular cancer whose primary and metastatic histology included seminoma, teratoma, embryonal carcinoma (EC), and yolk sac tumor (YST). In vitro, the cells have been maintained for more than 70 passages, produce alpha‐fetoprotein (AFP) and human chorionic gonadotropin (hCG), and have a human karyotype. When 2 × 107 cells of either line are inoculated into athymic mice, 87.5% of the animals (21/24) develop tumors. Initially 80% to 90% of the mass is EC, whereas the central portion is YST. After 90 to 390 days in vivo, the tumors achieve a large volume (2.13 ± 0.97 cm3), become cystic, and undergo histologic change. The peripheral rim of the mass remains EC, but the central 80% to 90% becomes YST. The sera of tumor‐bearing mice were positive for hCG and AFP in 11% and 38% of animals, respectively. Tumor cyst fluid was positive for hCG and AFP in 87% and 59% of animals, with mean values of 108 mIU/ml and 2,478 ng/ml, respectively. Tumor cyst fluid also contained placental alkaline phosphatase and human fibronectin. These two cell lines are useful for studies on the interrelationship of EC and YST and the differentiation of human germ cell cancer.

Identification of specific binding sites for leukotriene C4 in human fetal lung

Specific leukotriene C4 (LTC4)1 binding sites were identified in membrane preparations from human fetal lung. Specific binding of [3H]-LTC4 represented 95 percent of total binding, reached steady-state within 10 minutes and was rapidly reversible upon addition of excess unlabeled LTC4. Binding assays were performed at 4 degrees C under conditions which prevented metabolism of [3H]-LTC4 (80 mM serine-borate, 10 mM cysteine, 10 mM glycine). Under these conditions, greater than 95 percent of the membrane bound radioactivity, as analyzed by high performance liquid chromatography, co-eluted with the LTC4 standard. Computer-assisted analyses of saturation binding data showed a single class of binding sites with a dissociation constant (Kd) of 26 + 6 nM and a density (Bmax) of 84 + 18 pmol/mg protein. Pharmacological specificity was demonstrated by competition studies in which specific binding of [3H]-LTC4 was displaced by LTC4 and its structural analogs with inhibition constants (Ki) of 10 to 30 nM, whereas LTD4, diastereoisomers of LTD1, LTE4 and the end organ antagonist FPL 55712 were 150 to 700 fold less potent competitors than LTC4. These results provide evidence for specific, reversible, saturable, high affinity binding sites for [3H]-LTC4 in human fetal lung membranes.

Monoclonal antibody-targeted radiotherapy of renal cell carcinoma using a nude mouse model

Radiation dosimetry and monoclonal antibody (MAB)‐targeted radiotherapy studies were performed to evaluate the feasibility of using tumor‐preferential MAB as targeting agents for internal radiotherapy of renal cell carcinoma (RCC). Two human RCC xenograft lines, TK‐177G and TK‐82, were established in nude mice and studied using MAB A6H as a targeting agent. This MAB has previously demonstrated excellent in vivo localization to RCC xenografts. Two doses of A6H (13 to 19 μg) labeled with iodine 131 (110 to 130 μCi) caused the tumor to regress or arrested the tumor growth in both xenografts. Similar doses (18 to 43 μg; 120 μCi) of 131I‐labeled control MAB AFP‐22 or of unlabeled A6H did not inhibit tumor growth. While most mice in the control groups had tumors greater than 250 mg in weight by day 43, none of the tumors in mice treated with 131I‐labeled A6H grew to that size during the 3‐month observation period. Sequential computerized scintigraphy was used to calculate the amount of radioiso‐tope localized in tumor versus normal mouse tissue. Therapeutic doses of 131I‐labeled A6H delivered a median calculated radiation dose of 38 cGy/μCi (range, 28 to 57) injected dose to RCC xenografts, and a median of 0.9 cGy/μCi to normal mouse tissues. These findings suggest that A6H is able to target radioisotopes highly specifically to RCC and achieve a therapeutic effect in the experimental setting.

The Role of Calmodulin in Human Natural Killer Cell Activity

Calcium is known to play an essential role in the lytic mechanism of natural killer cells (NK), which form a subset of large granular lymphocytes. Many of the intracellular effects of calcium are mediated through the calcium‐binding protein calmodulin. In this study we have demonstrated that the specific calmodulin inhibitors (naphthalene‐sulphonamides) inhibit NK activity in humans at IC50s of 6.9 μM for W7 and 5.2 μM for W13. Comparison of the potency of these compounds with their less active counterparts suggests that NK activity is calmodulin‐dependent.

Monoclonal antibodies in urology

The recent development of hybridoma technology has made it possible to obtain large quantities of antibody against a single determinant (monoclonal antibodies). This review describes the history of hybridoma technology and the method of producing monoclonal antibodies. It examines the role of such antibodies in diagnosis, tissue typing, histochemistry, developmental biology and study and treatment of diseases, including cancer, emphasizing the work being done on urological diseases.

Differentiation potential of human embryonal carcinoma cell lines.

We have established 17 embryonal carcinoma (EC) cell lines from human testicular germ cell tumors by using three different methods of in vitro cultivation. Cultures of only three of these cell lines, and of clones derived from two of them, differentiate extensively when the cells are seeded at low density. A comparison is presented of the results obtained with the three methods used to establish and maintain these cell lines, and some properties of the three pluripotential EC lines are summarized.