Immunohistochemical localization of prostate-specific markers within the accessory male sex glands of Cowper, Littre, and Morgagni

Cowper Glands Identified in Prostate and Urethral Specimens: A Comprehensive Immunohistochemical Characterization and Potential Diagnostic Pitfall

Cowper glands recognition remains one of the key histoanatomic benign mimics of prostatic adenocarcinoma. In most instances, these can be identified based on the dimorphic population of lobulated acini and duct(s). However, in the prostate biopsy setting with incomplete/distorted cores, this may not be immediately apparent and may warrant use of immunohistochemistry to argue against prostatic adenocarcinoma. Although immunohistochemical pitfalls in Cowper glands have been described, to our knowledge a comprehensive evaluation of both traditional and purportedly prostate-specific novel markers in Cowper glands has not been previously performed. Herein, we studied the clinicopathological and immunohistochemical features of 21 male patients (age range 39-81 years; mean = 63 years), including 15 prostate biopsies (7 of which also had prostate cancer in the same specimen set and 2 of which had both prostate cancer and Cowper glands in the same biopsy core). Immunohistochemistry showed the following results in Cowper glands: 100% positive for NKX3.1, 100% positive (basal cells) for both high molecular weight keratin and p63, 57% positive for PSAP, 25% positive for PSMA, 5% positive for AMACR, and 0% positive for PSA. In conclusion, for specimens lacking appreciable dimorphic morphology, caution should be rendered when using prostate-specific markers (PSA, PSAP, PSMA, and NKX3.1) as these can show considerable staining in Cowper glands and be a pitfall. Instead, findings from this cohort indicate relying on basal markers (high molecular weight keratin/p63; either individually or in a "cocktail" approach) and PSA are most useful in distinguishing Cowper glands (retained basal cell markers staining) from prostatic adenocarcinoma.

Distribution of prostatic markers in glands of the female urethra and anterior vaginal wall-a rapid autopsy study

BACKGROUND

There are varying reports of immunohistochemically detected prostatic marker protein distribution in glands associated with the female urethra that may be related to tissue integrity at the time of fixation.

AIM

In this study we used tissue derived from rapid autopsies of female patients to determine the distribution of glandular structures expressing prostate-specific antigen (PSA) and prostate-specific acid phosphatase (PSAP) along the female urethra and in surrounding tissues, including the anterior vaginal wall (AVW).

METHODS

Tissue blocks from 7 donors that contained the entire urethra and adjacent AVW were analyzed. These tissue samples were fixed within 4-12 hours of death and divided into 5-mm transverse slices that were paraffin embedded. Sections cut from each slice were immunolabeled for PSA or PSAP and a neighboring section was stained with hematoxylin and eosin. The sections were reviewed by light microscopy and analyzed using QuPath software.

OBSERVATIONS

In tissue from all donors, glandular structures expressing PSA and/or PSAP were located within the wall of the urethra and were present along its whole length.

RESULTS

In the proximal half of the urethra from all donors, small glands expressing PSAP, but not PSA, were observed adjacent to the and emptying into the lumen. In the distal half of the urethra from 5 of the 7 donors, tubuloacinar structures lined by a glandular epithelium expressed both PSA and PSAP. In addition, columnar cells at the surface of structures with a multilayered transitional epithelium in the distal half of the urethra from all donors expressed PSAP. No glands expressing PSA or PSAP were found in tissues surrounding the urethra, including the AVW.

CLINICAL IMPLICATIONS

Greater understanding of the distribution of urethral glands expressing prostatic proteins in female patients is important because these glands are reported to contribute to the female sexual response and to urethral pathology, including urethral cysts, diverticula, and adenocarcinoma.

STRENGTHS AND LIMITATIONS

Strengths of the present study include the use of rapid autopsy to minimize protein degradation and autolysis, and the preparation of large tissue sections to demonstrate precise anatomical relations within all the tissues surrounding the urethral lumen. Limitations include the sample size and that all donors had advanced malignancy and had undergone previous therapy which may have had unknown tissue effects.

CONCLUSION

Proximal and distal glands expressing prostate-specific proteins were observed in tissue from all donors, and these glands were located only within the wall of the urethra.

Prostate-Specific Antigen as an Ultrasensitive Biomarker for Patients with Early Recurrent Prostate Cancer: How Low Shall We Go? A Systematic Review

Serum prostate-specific antigen (PSA) needs to be monitored with ultrasensitive PSA assays (uPSAs) for oncologists to be able to start salvage radiotherapy (SRT) while PSA is <0.5 µg/L for patients with prostate cancer (PCa) relapsing after a radical prostatectomy (RP). Our systematic review (SR) aimed to summarize uPSAs for patients with localized PCa. The SR was registered as InPLASY2023110084. We searched for studies on Google Scholar, PUBMED and reference lists of reviews and studies. We only included studies on uPSAs published in English and excluded studies of women, animals, sarcoidosis and reviews. Of the 115 included studies, 39 reported PSA assay methods and 76 reported clinical findings. Of 67,479 patients, 14,965 developed PSA recurrence (PSAR) and 2663 died. Extremely low PSA nadir and early developments of PSA separated PSAR-prone from non-PSAR-prone patients (cumulative p value 3.7 × 1012). RP patients with the lowest post-surgery PSA nadir and patients who had the lowest PSA at SRT had the fewest deaths. In conclusion, PSA for patients with localized PCa in the pre-PSAR phase of PCa is strongly associated with later PSAR and survival. A rising but still exceedingly low PSA at SRT predicts a good 5-year overall survival.

Imaging of the Bulbourethral (Cowper) Gland: Abnormalities and Differential Diagnosis

Normal Cowper glands and ducts are imperceptible at imaging. However, abnormalities of the Cowper glands and ducts are increasingly seen owing to increasing use of cross-sectional imaging. In this article, the authors present a comprehensive review of the normal anatomy of the Cowper glands and ducts and the clinical and imaging findings of conditions that affect them in an effort to help lead to appropriate diagnosis and management. A Cowper duct syringocele is a congenital or acquired dilatation of the Cowper duct in the bulb of the corpus spongiosum. Retrograde urethrography is the standard test to diagnose a communicating (open) Cowper duct syringocele, and MRI is used for further morphologic assessment. Cowperitis refers to inflammation of the gland and/or duct, and recurrent cowperitis is usually associated with an underlying syringocele, a urethral fistulous connection to the Cowper gland, or a perianal fistula. MRI allows detection of the underlying structural abnormality and the superimposed inflammation. Cowper stones are typically radiopaque and are found in both the Cowper gland and duct. A Cowper gland HHhemorrhagic cyst may be incidentally detected at MRI of the prostate, and follow-up MRI may be required to ensure evolution of hemorrhage and exclude an underlying neoplasm. Cowper gland carcinoma is rare and includes adenocarcinoma and adenoid cystic carcinoma subtypes. Transperineal US may be used for initial evaluation and CT and/or MRI are necessary for further characterization and staging. Cowper gland hyperplasia is a rare entity with few previous reports that may be incidentally detected at imaging and may mimic malignancy. ^©RSNA, 2022.

Biochemical Characteristics and Recent Biological Knowledge on Prostate-Specific Antigen

Since its identification in seminal fluid in 1971, much new information has been obtained about the biology and expression of prostate-specific antigen (PSA). PSA is a glycoprotein composed of 93% amino acids and 7% carbohydrates, with a molecular weight of about 30,000 Da. Functionally and structurally PSA is a kallikrein-like serine protease, and its physiologic role is degradation of the major proteins of seminal coagulum (semenogelin I and II, fibronectin), which leads to semen liquefaction. The PSA gene is located on the 13q region of chromosome 19, and it has a high degree of homology (more than 80%) with genes of the human glandular kallikrein (hKGK1). PSA production and expression are preferentially but not exclusively associated to the normal, benign hyperplastic and cancerous tissues of the prostate. In fact, it has been demonstrated that PSA is also present in accessory male sex glands and breast cancer. It was recently reported that PSA was also present in milk of lactating women. Many factors may influence PSA synthesis and production, and among them the most important are androgen, retinoic acid and growth factor stimulation. Significant advances have been recently made as regards the molecular isoforms of PSA. In the seminal fluid PSA seems partially bound to a serpine (protein C inhibitor), whereas in serum it is predominantly associated to α-1-antichymotrypsin and in a small quantity to α-2-macroglobulin. These new findings will have implications for the clinical application of PSA as a tumor marker for prostate cancer.

Ectopic prostatic tissue: histogenesis and histopathological characteristics

AIMS

To evaluate the histological and immunohistochemical characteristics of ectopic prostatic tissue.

METHODS AND RESULTS

We studied 20 cases of ectopic prostate. In 85% (17/20) of the cases, the ectopic prostatic tissue was located in the bladder; in the remaining cases, it was located in the urethra. In 60% of the cases (12/20), no significant inflammatory or reactive/reparative changes were identified in the adjacent tissue. Immunohistochemical stains for prostate-specific antigen, prostate-specific acid phosphatase, and prostein were positive in the glandular epithelial cells of all cases. Stains for 34βE12 and p63 confirmed the presence of basal cells in all cases. There was no overexpression of α-methylacyl-CoA racemase in any of the cases. There was cytoplasmic luminal staining for CD10 and cytoplasmic staining for cytokeratin 18 in acinar cells in all cases. In cases in which followup data were available, no patient was found to have residual or recurrent ectopic prostatic tissue and none developed prostatic adenocarcinoma.

CONCLUSIONS

Ectopic prostatic tissue is occasionally encountered in the lower urinary tract, most commonly in the bladder and urethra of males. Ectopic prostatic tissue has histological and immunohistochemical characteristics that are indistinguishable from those of normal prostatic tissue, and most likely represents the persistence of embryonic structures.

A neglected gland: a review of Cowper's gland

Cowper's glands are pea sized glands present inferior to the prostate gland in the male reproductive system. They produce thick clear mucus prior to ejaculation that drains into the spongy urethra. Though it is well established that the function of the Cowper's gland secretions is to neutralize traces of acidic urine in the urethra, knowledge regarding the various lesions and associated complications of this gland is scarce. This review provides a comprehensive report on the development, function and various lesions associated with Cowper's gland.

Immunohistochemistry in diagnostic surgical pathology of the prostate

Immunohistochemistry (IHC) can play an important role in diagnostic surgical pathology of the prostate. Basal cell markers, such as the 34betaE12 antibody and antibodies directed against cytokeratin 5 and 6 or p63, are very useful for demonstration of basal cells as their presence argues against a diagnosis of invasive prostatic carcinoma (PC). However, several benign mimickers of PC, including atrophy, atypical adenomatous hyperplasia (AAH), nephrogenic adenoma, and mesonephric hyperplasia, can stain negatively with these markers, and thus, a negative basal cell marker immunostain alone does not exclude a diagnosis of benignancy. Although there are examples in the literature of high grade PC that stain focally with some of the basal cell markers, these cases are usually readily diagnosed based on H&E appearances and are unlikely to be confused with these benign mimickers. Alpha-methylacyl-coenzyme-A racemase (AMACR) is a sensitive marker of PC (except for a few uncommon variants: atrophic, foamy gland, and pseudohyperplastic variants), and its detection by immunohistochemical staining in atypical prostatic lesions can be very useful in confirming an impression of adenocarcinoma. AMACR expression can also be identified in high grade prostatic intraepithelial neoplasia (PIN), prostatic atrophy, AAH, and benign prostatic glands, and accordingly, a diagnosis of PC should not be based solely on a positive AMACR immunostain, especially when the luminal staining is weak and/or noncircumferential. The use of AMACR/basal cell antibody cocktails has been found to greatly facilitate the distinction between PC and its benign mimickers, especially when only limited tissue is available for staining. Prostate specific antigen (PSA) and prostate specific acid phosphatase (PSAP) are both quite sensitive and fairly specific markers of PC (there are a few nonprostatic tumors that can express one or both), and are both very helpful in establishing or confirming the diagnosis of PC when the differential diagnosis includes other tumors that can involve the prostate such as urinary bladder urothelial carcinoma. 34betaE12, p63, thrombomodulin, and uroplakin III are additional urothelial associated markers useful in this differential diagnosis. CDX2 and villin are useful markers to diagnostically separate colonic adenocarcinoma from PC. AMACR positivity and negative basal cell marker reactions are useful to confirm the presence of residual PC after hormonal or radiation therapy. Pan-cytokeratin, PSA, and PSAP can also highlight subtle infiltrates of PC with hormonal or radiation therapy effect. PSA and PSAP immunohistochemical stains are valuable in confirming metastatic carcinoma as being of prostatic origin and should always be utilized in the diagnostic evaluation of metastatic adenocarcinoma of unknown primary origin in males.

Congenital urethral cysts in boys with vesicoureteric reflux

Four cases of congenital urethral cysts are reported. Diagnosis was made by endoscopy. The coincidence of urethral cysts and vesicoureteric refluxes seemed incidental in three cases. Fetal infravesical obstruction was provable in the fourth infant.

CONCLUSION

Urethral cysts should be considered in boys with vesicoureteric reflux. For the vast majority of cases it seems improbable that urethral cysts play a role in the pathogenesis of congenital vesicoureteric reflux.

The role of molecular forms of prostate-specific antigen (PSA or hK3) and of human glandular kallikrein 2 (hK2) in the diagnosis and monitoring of prostate cancer and in extra-prostatic disease

Prostate-specific antigen (PSA or hK3) is a glandular kallikrein with abundant expression in the prostate that is widely used to detect and monitor prostate cancer (PCa), although the serum level is frequently elevated also in benign and inflammatory prostatic diseases. PSA testing is useful for early detection of localized PCa and for the detection of disease recurrence after treatment. However, PSA has failed to accurately estimate cancer volume and preoperative staging. There is no PSA level in serum that definitively distinguishes men with benign conditions from those with prostate cancer, although PCa is rare in men with PSA levels in serum < 2.0 ng/ml. This prompted searches for enhancing parameters to combine with PSA testing, such as PSA density, PSA velocity, and age-specific reference ranges. Due to the protease structure, PSA occurs in different molecular forms in serum and their concentrations vary according to the type of prostatic disease. Human glandular kallikrein 2 (hK2) is very similar to PSA, but expressed at higher levels in prostate adenocarcinoma than in normal prostate epithelium. Blood testing for hK2 combined with different PSA forms improves discrimination of men with benign prostatic disease from those with prostate cancer. Many data have also been reported on the extra-prostatic expression of both PSA and hK2, and it is now believed that they may both have functions in tissues outside the prostate.

Expression of prostate-specific antigen and human glandular kallikrein 2 in the thyroid gland

Prostate-specific antigen (PSA) and human glandular kallikrein 2 (hK2) are two closely related kallikreins, primarily produced by the prostate. These serine proteases are now used as biomarkers for the diagnosis and management of prostate cancer. Until recently, PSA and hK2 were thought to be strictly expressed in the prostate; however, numerous studies confirmed their presence in various biological fluids as well as in many normal and malignant tissues. Using reverse transcription-polymerase chain reaction (RT-PCR), we screened RNA extracted from 26 different normal tissues and found that both genes are expressed in the thyroid. Subsequently, we analyzed 15 RNAs extracted from thyroid tissues (10 benign and 5 malignant lesions) and found that both kallikreins were expressed in five specimens (four benign lesions and one malignant). Sequencing of the PCR products confirmed the specificity of our experiments. Immunohistochemistry localized PSA in oxyphilic cells of thyroid tissue. These data confirm expression of both PSA and hK2 in thyroid tissue and suggest that oxyphils are the source of their production. The function of these two proteases in thyroid tissue is unknown.

[Mucinous carcinoma of the prostate: critical review of Elbadawi's criteria]

OBJECTIVES

We present our experience on prostatic mucinous adenocarcinoma and at once we practice an actualization and a critical review of Elbadawi's criteria.

METHODS

After reviewing 206 prostatic carcinomas diagnosed in our hospital, we describe one case that fulfill criteria for being considered a prostatic mucinous adenocarcinoma. We also carry out a wide literature review trying to define anew the including criteria of this tumour by the light of modern knowledge and technology.

CONCLUSIONS

We think that for accepting a tumour as a prostatic mucinous adenocarcinoma, this have to fulfill the following criteria: 1. "More than 25% of a significative tumoral sample is mucinous pattern and present, single or clustered, tumour cells floating in immunohistochemically probed, acidic and neutral, mucin lakes". 2. "Tumour is Gleason 3-4 cribiform pattern with direct transition to colloid areas and usually coexist with classic adenocarcinoma but papillary growth patterns should be excluded. Tumour may contain a moderate proportion of signet-ring cells". 3. "Immunohistochemical staining for PSA have to be strongly positive in both, cribiform and mucinous, areas". 4. "Those PSA nonreactive, or only focally positive, mucinous adenocarcinomas, could be labeled as prostatic only when local or distant mucinous carcinomas are ruled out".

The diagnostic and prognostic utility of prostate-specific antigen for diseases of the breast

Although prostate-specific antigen (PSA) is the most valuable tumor marker for the diagnosis and management of prostate carcinoma, it is widely accepted that PSA is not prostate specific. Numerous studies have shown that PSA is present in some female hormonally regulated tissues, principally the breast and its secretions. In this review, we summarize the findings of PSA in the breast, and focus on its potential for clinical applications in breast disease. PSA is produced by the majority of breast tumors and is a favorable indicator of prognosis in breast cancer. Low levels of PSA are released into the female circulation, and while the level of serum PSA is elevated in both benign and malignant breast disease, the molecular form of circulating PSA differs between women with and without breast cancer. These findings indicate that PSA may have potential diagnostic utility in breast cancer. PSA may also have a clinical application in benign breast disease, as both the level and molecular form of PSA differ between Type I and II breast cysts. High levels of PSA have been reported in nipple aspirate fluid (NAF) and recent studies have shown that the concentration of PSA in NAF is inversely related to breast cancer risk, indicating that NAF PSA may represent a clinical tool for breast cancer risk assessment. Thus, PSA represents a marker with numerous potential clinical applications as a diagnostic and/or prognostic tool in breast disease.

Prostate-specific antigen in acute hepatitis and hepatocellular carcinoma

BACKGROUND

Prostate-specific antigen (PSA) is the most important tumor marker in prostate cancer diagnosis and follow-up. Its catabolism by the liver has not influenced its use as a prostate marker until the recent report of a significant increase in a man and a woman with acute hepatitis. In addition, PSA was detected in liver tumor extracts, which warranted its evaluation in liver cytolysis and hepatocellular carcinoma. In this study, PSA was evaluated in a cohort of both sexes presenting either acute hepatitis or hepatocellular carcinoima.

METHODS

Forty-two patients with acute hepatitis (21 male patients, 21 female patients) and 54 patients with hepatocellular carcinoma (31 male patients, 23 female patients) were tested for PSA by equimolar immunoassay (Abbott AxSYM Total PSA, Abbott Diagnostics, Rungis, France) and for relevant liver biological parameters (alpha-fetoprotein, alanine aminotransferase, aspartate aminotransferase, total bilirubin, and prothrombin rate).

RESULTS

PSA was undetectable in all the female patients and was consistent with age in the males (PSA median and range in acute hepatitis, 0.36 microg/l (range, 0.05-1.3); in hepatocellular carcinoma, 0.36 microg/l (range, 0.02-3.9)). It did not correlate with alpha-fetoprotein and aminotransferases.

CONCLUSIONS

Our results confirm the well-established reliability of PSA, and show that PSA remains a valid prostate marker in patients with acute hepatitis and hepatocellular carcinoma.

Human Glandular Kallikrein in Breast Milk, Amniotic Fluid, and Breast Cyst Fluid

Background: Human glandular kallikrein (hK2) belongs to the serine protease family of enzymes and has high sequence homology with prostate-specific antigen (PSA). The physiological role of hK2 has not as yet been determined, but there is evidence that it can regulate the proteolytic activity of PSA through processing and activating pro-PSA, an inactive precursor. Thus, it is conceivable that these two secreted proteins may coexist in biological fluids. Currently, hK2 is considered an androgen-regulated and prostate-specific protein. Recently, it has been demonstrated that hK2 is expressed in the breast cancer cell line T-47D after stimulation by steroid hormones, and we reported that hK2 can be detected in a subset of breast tumor extracts. These data suggest that hK2 may be expressed in tissues other than the prostate, such as those in which PSA has already been detected. Because hK2 is a secreted protein, it may be present in various biological fluids.

Methods: We analyzed milk samples from lactating women, amniotic fluid from pregnant women, and breast cyst fluid from patients with gross breast cystic disease, using a highly sensitive and specific immunoassay for hK2.

Results: hK2 was present in all three biological fluids. We suggest that the female breast may produce hK2 and provide evidence that hK2 may have value as an additional marker for the discrimination between type I and type II breast cysts.

Conclusions: The female breast produces hK2 in addition to PSA. More studies are necessary to establish the role of this kallikrein in nondiseased breast, gross breast cystic disease, and breast cancer.

Diagnosis of Cowper's glands on prostate needle biopsy

The presence of normal anatomic structures may be a source of confusion to the pathologist examining prostatic needle biopsies. The morphologic features of Cowper's (bulbourethral) glands incidentally biopsied during transrectal sampling of the prostate have not been described. We reviewed seven cases of Cowper's glands found in prostatic core biopsy specimens. Sections containing Cowper's glands were stained with hematoxylin-eosin, mucicarmine, periodic acid-Schiff's-digest (PAS-D), and antibodies directed at high-molecular-weight cytokeratin (HMWCK), prostate-specific acid phosphatase (PSAP), prostate-specific antigen (PSA), Ulex europaeus agglutinin, and muscle-specific actin. Histologically, Cowper's glands resemble mucinous minor salivary glands entrapped within fascicles of muscle. Lobules of acini composed of cells distended with mucin (mucicarmine and PAS-D positive) were admixed with ducts and ductules composed of hybrid cells with both mucinous and ductular epithelial features. The HMWCK was strongly reactive with the ductular epithelium and demonstrated an attenuated cell lining at the periphery of lobules. The mucinous cytoplasm reacted with U. europaeus, whereas the ductal elements failed to stain. PSAP stains were negative, with PSA positive in most cases. Muscle-specific actin was positive in three cases. Cowper's glands occasionally may be sampled by transrectal needle biopsy. Recognition of this anatomic structure will allow discrimination from low-grade prostatic adenocarcinoma, foamy gland carcinoma, mucinous metaplasia of prostate glands, and atypical glands of undetermined significance.

Constitutive expression of high levels of prostate-specific antigen in the absence of prostate carcinoma

OBJECTIVES

To identify distinguishing serologic features in patients with stable marked elevation in prostate-specific antigen (PSA) and multiple negative biopsies.

METHODS

The study population consisted of 7 patients with a stable PSA level of greater than 20 ng/mL (average 27.0), followed for at least 34 months (average 56), and with two or more negative prostatic biopsies including transition zone biopsies. The PSA density (PSAD), rate of change in PSA, reverse transcriptase/polymerase chain reaction (RT/PCR), and free/total PSA were obtained.

RESULTS

Rate of change in PSA level was stable (0.18 +/- 1.2 ng/mL/yr), suggesting that there was no occult cancer; PSAD was high (0.34 +/- 0.5 ng/mL/cc), indicating that prostate size was not the sole cause of the elevation. The RT/PCR was negative in 6 of 7 patients, further decreasing the likelihood of an occult malignancy. Free versus total PSA was not consistent, averaging 16.8%, but with a range of 6% to 34%.

CONCLUSIONS

Novel PSA tests were not found to be useful in this cohort of patients with multiple negative biopsies and PSA elevations greater than 20 ng/mL. Additional studies with larger sample size are required to confirm this finding.

Detection of prostate specific antigen in pancreas and salivary glands: a potential impact on prostate cancer overestimation

PURPOSE

We explored the immunohistochemical expression of prostate specific antigen (PSA) in pancreas and salivary glands.

MATERIALS AND METHODS

We investigated 62 specimens from male and female subjects, representing normal cases and several pathological conditions of pancreas and salivary glands. Two commercially available monoclonal antisera for PSA and 1 for prostatic acid phosphatase were used.

RESULTS

A consistently positive reaction for PSA and prostatic acid phosphatase, independent of patient sex, was noted in ductal cells of normal pancreas and normal salivary glands, as well as pleomorphic adenoma, adenocarcinoma and all oncocytic epithelial cells of Warthin's tumor. Reaction was absent in normal stromal and acinar cells, and squamous carcinoma.

CONCLUSIONS

PSA is detectable in normal and cancer tissues far from the prostate. Therefore, we may not entirely rely on specificity of PSA alone to diagnose metastatic prostate cancer.

PSA divergence. A new parameter for the accurate longitudinal assessment of prostatic disease

Prostate-specific antigen (PSA) and the various parameters derived utilizing this marker have increased our ability to diagnose early prostatic disease; however, their accuracy in identifying the etiology of the disease remains somewhat limited. We propose a new PSA derivative, termed "PSA divergence" (PSADI), defined as the change in serum PSA over time (years) divided by the change in prostatic volume over time (years), to more accurately distinguish benign, premalignant, and malignant prostatic diseases. In this study, we evaluated 160 subjects with a PSA >4.0 ng/ml who were found by transrectal ultrasound-guided biopsy (TRUS) to have either benign prostatic hyperplasia or prostatic intraepithelial neoplasia. These men were followed at 6 or 12 months with serial PSA, digital rectal exam (DRE), and TRUS with rebiopsy. Data analysis demonstrated a statistically significant (p < 0.05) correlation between PSADI and each final pathologic outcome, suggesting that PSADI is useful in distinguishing among intraepithelial neoplasia and benign and malignant prostatic disease.

Immunohistochemical labelling for prostate specific antigen in non-prostatic tissues

Immunohistochemical detection of prostate specific antigen (PSA) in metastases of adenocarcinomas is widely used as an aid to identify the prostatic origin of metastatic cells. However, on the one hand, PSA may not be expressed in some poorly differentiated prostatic carcinomas, while on the other, PSA immunoreactivity has been found in small amounts in non-prostatic tissues. The aim of the current study was to evaluate the prevalence of PSA immunoreactivity in normal non-prostatic tissues and in breast carcinoma. PSA was localized by immunohistochemistry with four commercial antibodies in 34 different normal human tissues, and in 15 ductal and seven apocrine breast carcinomas. Concentrations of PSA in tissue homogenates of prostate and nine non-prostatic tissues from autopsied subjects were measured by a two-site immunoradiometric assay. Weak PSA immunoreactivity was found by immunohistochemistry in kidney, parotid gland and pancreatic tissues. Variable PSA immunoreactivity was seen in three cases of ductal (20%) and two cases of apocrine breast carcinoma (28%). No consistent PSA immunoreactivity was found in homogenates of non-prostatic tissues by the immunoradiometric assay. We conclude that PSA is a quite specific marker of prostatic tissue. However, there are some non-prostatic neoplastic and normal tissues that express PSA. Therefore, a definite diagnosis of metastasis of prostatic origin cannot be made on the basis of immunolabelling for PSA alone.

Biochemical characteristics and biological profile of prostate specific antigen (PSA)

Since its identification in seminai fluid in 1971, a tot more knowledge has been obtained about the biology and expression of prostate specific antigen (PSA). PSA is a glycoprotein consisting of 93% aminoacids and 7% carbohydrates with a molecular weight of about 30000 dalton. Functionally and structurally PSA is a kallikrein-like serine protease and its physiological role is the degradation of the major proteins of the seminal coagulum (semenogelin I and II, fibronectin) leading to semen liquefaction. The PSA gene is located on the 13q region of chromosome 19 and has a high degree of homology (more than 80%) with the gene of human glandular kallikrein (hGK1). PSA production and expression are preferentially but not exclusively associated with the normal, benign hyperplastic and cancerous tissues of the prostate. In fact, it has been demonstrated that PSA is also present in the accessory male sex glands of Cowper, Littre and Morgagni and other extra-prostatic neoplasms, such as salivary gland tumours and breast cancer. Many factors may influence PSA synthesis and production and among them the most important are androgen and growth factor stimulation. Advances have recently been made on the molecular isoforms of PSA. In the seminai fluid PSA seems partially bound to a serpine (protein C inhibitor), whilst in the serum PSA is predominantly associated to α-antichymotrypsin (ACT) and in low quantity to α2-macroglobulin (α2M). All these findings will have implications on clinical applications of PSA as a tumour marker for prostate cancer.

False-positive serum prostate-specific antigen values in a patient with non-Hodgkin lymphoma of the kidney

Prostate-specific antigen (PSA) is the clinically most useful tumor marker for prostate cancer. Although false-positive elevations have been reported due to disease processes outside the prostate gland with the use of the polyclonal assay, such false-positive test results have been exceedingly rare with the use of the monoclonal assay. We report the case of a patient diagnosed with a B-cell lymphoma of the kidney and a significant elevation of serum PSA levels by monoclonal assay in the absence of either inflammatory or malignant prostate disease. PSA returned to normal during lymphoma-specific chemotherapy with a cyclophosphamide, mechlorethamine, vincristine, procarbazine, prednisone regimen. Possible explanations and clinical implications are discussed.