Combination of Autoantibody Signature with PSA Level Enables a Highly Accurate Blood-Based Differentiation of Prostate Cancer Patients from Patients with Benign Prostatic Hyperplasia

Although an increased level of the prostate-specific antigen can be an indication for prostate cancer, other reasons often lead to a high rate of false positive results. Therefore, an additional serological screening of autoantibodies in patients’ sera could improve the detection of prostate cancer. We performed protein macroarray screening with sera from 49 prostate cancer patients, 70 patients with benign prostatic hyperplasia and 28 healthy controls and compared the autoimmune response in those groups. We were able to distinguish prostate cancer patients from normal controls with an accuracy of 83.2%, patients with benign prostatic hyperplasia from normal controls with an accuracy of 86.0% and prostate cancer patients from patients with benign prostatic hyperplasia with an accuracy of 70.3%. Combining seroreactivity pattern with a PSA level of higher than 4.0 ng/ml this classification could be improved to an accuracy of 84.1%. For selected proteins we were able to confirm the differential expression by using luminex on 84 samples. We provide a minimally invasive serological method to reduce false positive results in detection of prostate cancer and according to PSA screening to distinguish men with prostate cancer from men with benign prostatic hyperplasia.     

The contribution of prostatic acid phosphatase and prostatic specific antigen in the diagnosis of prostatic cancer

Prostatic acid phosphatase (PAP) and prostatic specific antigen (PSA) were measured by immunochemical methods using test preparations from two different companies. In 66 patients with benign hyperplasia of the prostate a good correlation was found only between PSA levels (orthogonal regression analysis: y = 1.77 x -0.68; r = 0.995). Discrimination analysis between benign hyperplasia and new prostatic cancer (28 patients), using ROC curves, revealed a sensitivity for prostatic cancer of about 30 percent using both PAP methods and of about 58 percent using both PSA methods at the 95-percentile of benign hyperplasia. The PSA methods were both more sensitive in detecting prostatic cancer than the PAP methods.     

Benign prostatic hyperplasia: does prostate size matter?

Recent studies and analyses have confirmed that baseline prostate volume is related to progression of benign prostatic hyperplasia (BPH) as well as to negative outcomes related to BPH, such as acute urinary retention (AUR) and need for surgery, and can also predict response to therapy. Other investigations have determined that prostate-specific antigen (PSA) level has good predictive value for assessing prostate volume. Strong evidence exists that baseline serum PSA level, like baseline prostate volume, predicts future prostate growth. Randomized placebo-controlled finasteride trials have shown that men with larger prostate volumes and higher PSA levels experience a clinically significant response to therapy compared with those with smaller prostate volumes and lower PSA levels. It has also been demonstrated that men with larger prostate glands and higher PSA levels are at increased risk for AUR and BPH-related surgery but that finasteride reduces these risks. Moreover, doxazosin and finasteride, alone and in combination, have been shown to significantly reduce BPH clinical progression.     

Contribution of Genetic Variation rs266882 to Prostate-Specific Antigen Levels in Healthy Controls with Serum PSA Below 2.0 ng/ml

We evaluated the impact of genetic variation in the prostate-specific antigen (PSA) gene (rs266882) on serum PSA levels in healthy men as well as risk factors for benign prostate hypertrophy (BPH) and prostate cancer. The study population comprised 91 men with PSA levels below 2.0 ng/ml as healthy controls, 78 men with PSA 2–10 ng/ml as a BPH group, and 128 prostate cancer patients, all in Korea. DNA was amplified by polymerase chain reaction and the product was sequenced. We found that PSA levels were associated with a G/A polymorphism only in healthy controls. The transition, however, was not associated with PSA levels of BPH and cancer patients, nor was it a risk factor. In conclusion, this genetic factor is important for determining serum PSA levels in the naive group, whereas the disruption of prostatic architecture in BPH or prostate cancer may be a major determining factor for PSA levels.     

Clinical behaviour of prostatic specific antigen and prostatic acid phosphatase: a comparative study

We assayed prostatic specific antigen (PSA) and prostatic acid phosphatase (PAP) serum levels in 1383 patients using a double antibody radioimmunoassay (RIA) I125. Establishing the upper normal limit in 10 ng/ml PSA and 2.5 ng/ml for PAP, the false positive results were only 1.9 and 5.1 percent in men with non-prostatic benign or malignant pathology and respectively 0 and 2.2 percent in women. We detected false positive levels for these two tumoral markers in 3.5 and 4.7 percent of patients with non-complicated benign prostatic hypertrophy, 64.8 and 19.2 percent in complicated benign prostatic hypertrophy, 24 and 16 percent in acute prostatitis and 3.3 percent in chronic prostatitis. The sensitivity in patients with prostate cancer was 87.2 percent for PSA and 64.1 percent for PAP, and there was a better correlation with PSA than PAP for tumoral spread and histological grading. Finally, clinical efficacy was higher with PSA and was no better when both markers were assayed.     

Expression and purification of recombinant active prostate-specific antigen from Escherichia coli

Human prostate-specific antigen (PSA), a 33 kDa serine protease with comprehensive homology to glandular kallikrein, is secreted from prostatic tissue into the seminal fluid and enters into the circulation. The level of PSA increases in the serum of patients with prostatic cancer and hence is widely employed as a marker of the disease status. In particular, an enzymatically active PSA that is a form cleaved at the N-terminal seven-amino-acids prosequence, APLILSR, of proPSA may play an important roll in the progression of prostate cancer. Thus, the presence of the active form would selectively discriminate the cancer from benign prostatic hyperplasia. In this study, we developed a convenient purification method for the acquisition of active PSA and proPSA. Recombinant proPSA and active PSA were expressed directly in Escherichia coli, easily and efficiently isolated from inclusion bodies, refolded, and purified. Moreover, the enzymatic activity of the recombinant active PSA was confirmed as serine protease using chromogenic chymotrypsin substrate. This purified active PSA could be further applied to scrutinize the biological or conformational characteristics of the protein and to develop specific diagnostic and/or therapeutic agents against prostate cancer.     

Cancer de la prostate : les marqueurs biologiques

Normal prostate cells and prostate cancer cells produce prostate-specific antigen (PSA): thus, it is frequently increased in non-malignant conditions such as prostatitis and benign prostatic hyperplasia. Indeed, PSA is an excellent biomarker to monitor disease progression. The low diagnostic specificity of PSA leads to many false-positive and a large number of biopsies. These well-recognized limitations of PSA suggest that new prostate cancer biomarkers could play a useful role in reducing the number of unnecessary biopsies.     

5-alpha-Reductase Inhibitors Prevent the Progression of Benign Prostatic Hyperplasia

Lower urinary tract symptoms (LUTS) associated with clinical benign prostatic hyperplasia (BPH) are a common occurrence in aging men, causing bother and interference with daily activities and affecting disease-specific quality of life. There is increasing evidence to suggest that, in many patients, the signs and symptoms of BPH are progressive. Progression can be measured as continued growth of the prostate gland; worsening of symptoms, bother, or quality of life; deterioration of urinary flow rate; episodes of acute urinary retention (AUR); and need for prostate-related surgery. Furthermore, it has become clear that the risk of disease progression increases with age as well as with increasing prostate volume and serum prostate-specific antigen (PSA) level. The 5-alpha-reductase inhibitor finasteride has been shown not only to improve symptoms, bother, and quality of life but also to prevent progression to AUR and surgery, with a relative risk reduction of over 50%. As the risk for such progression is higher in patients with larger glands or higher serum PSA values at baseline, it is in those patients that finasteride induces an even greater risk reduction, making it a cost-effective treatment choice for patients with LUTS associated with prostatic enlargement.     

Expression of prostate specific membrane antigen (PSMA) in prostatic adenocarcinoma and prostatic intraepithelial neoplasia

The prostatic membrane antigen (PSMA) is a protein that is expressed in the prostatic epithelium. We studied the expression of PSMA in a series of 55 patients with different stages of prostate cancer and we compared the PSMA staining in prostate cancer cells, in high-grade prostatic intraepithelial neoplasia (PIN) and in histologically benign prostatic epithelium for the same specimen. For this purpose archival paraffin-embedded specimens were studied by immunohistochemistry with a monoclonal antibody 7E11-C5.3 against PSMA using the streptavidin-biotin method. The mean percentage of PSMA immunoreactivity was 56.67% in prostate cancer (CaP) cells, and 48.6% in PIN cells, which was significantly higher than benign-appearing prostatic epithelium (5.72%) (for each pair, p<0.001). PSMA expression was greater in CaP with a higher Gleason score (p=0.01), but no relationship was found with serum PSA value. We conclude that PSMA overexpression is detected in high-grade PIN and is associated with a higher Gleason score of prostate cancer. It is a potential marker for studying carcinogenesis and progression of prostate cancer.     

Malondialdehyde in benign prostate hypertrophy: a useful marker?

Benign prostate hypertrophy (BPH) is the most common benign tumor in men due to obstruction of the urethra and, finally, uremia. Malondialdehyde (MDA) is a product derived from peroxidation of polyunsaturated fatty acids and related esters. Evaluation of MDA in serum represents a non-invasive biomarker of oxidative stress. Prostate-specific antigen (PSA) is a sensitive marker for prostatic hypertrophy and cancer. We analyzed MDA serum levels to evaluate the oxidative stress in BPH. To this end, 22 BPH patients and 22 healthy donors were enrolled. Data show an increase of MDA level in BPH patients and a positive correlation between PSA and MDA levels. In conclusion, we describe a previously unknown relationship between PSA and MDA as an index of inflammation and oxidative stress in BPH.     

Serum prostate-specific antigen determination in prostatic carcinoma

Prostate-specific antigen (PSA) is a tissue-specific glycoprotein identified by Wang in 1979. It is synthesized in the prostate independently of prostatic acid phosphatase (PAP). A total of 199 subjects were divided into four groups: controls aged less than 50 years, controls aged more than 50 years, patients with benign prostatic hyperplasia (BPH) and patients with prostatic carcinoma. PSA cut-off value was set at 10 ng/ml (mean for the BPH group plus 2 SD). With this cut-off value PSA could not be used as an early predictor of prostatic carcinoma. The association of PSA and PAP in prostatic cancer increases the number of patients with positive biological markers.     

Role of screening in detection of clinically localized prostate cancer

The aim of this study was to confirm the role of screening by determining the percentage of clinically localized prostate cancer (stage A and B) in patients with prostate cancer detected on screening and in those presenting to urologic clinic for the symptoms of urination impairment or ostalgia. During the study, 1,000 men aged > or = 50 from the community of Cepin and village of Josipovac near Osijek were examined. The subjects with elevated concentration of total prostate specific antigen and/or digital rectal examination suspect of carcinoma underwent transperineal biopsy of the prostate. Clinical staging was performed in patients with prostate cancer detected on screening, and data on clinical staging for prostate cancer patients treated during the 1996-1997 period were retrieved from patient files of the Department of Urology, University Hospital "Osijek". On screening, 28 (80%) patients with localized prostate cancer and seven (20%) patients with metastases were detected. In the group of patients examined on an outpatient basis for the signs and symptoms of prostatism, there were 30 (83.4%) patients with metastases and only six (16.6%) patients with localized prostate cancer. Study results indicated that an early diagnosis of prostate cancer could be made by use of noninvasive and inexpensive methods that cause no major discomfort to the patient. Accordingly, these results appear to strongly support such screening in men, if not in all those aged over 50, then at least in the otherwise healthy, 50-70 age group.     

Analysis of relations between serum levels of epitestosterone, estradiol, testosterone, IGF-1 and prostatic specific antigen in men with benign prostatic hyperplasia and carcinoma of the prostate

Epitestosterone competes with testosterone for androgen receptors and inhibits several enzymes of steroidogenesis. Insulin-like growth factors (IGFs) stimulate the growth of prostate cells and directly activate androgen receptors in prostatic tumor cell lines. The prostate-specific antigen (PSA) decreases the affinity of IGF-binding protein-3. The samples were collected from 71 patients suffering from various diseases of the prostate (56 patients without prostate cancer but with benign prostatic hyperplasia and 15 patients with prostate cancer). Correlations between age and IGF-1 (r = -0.281, p<0.05), age and serum epitestosterone (r = -0.261, p<0.05), estradiol and testosterone (r = 0.367, p<0.01), and between estradiol and epitestosterone (r = -0.414, p<0.001) were found. After age adjustment, IGF-I correlated with epitestosterone (r = -0.277, p<0.05). The age correlated positively with PSA (r = 0.286, p<0.05) and negatively with IGF-1 (r = -0.377, p<0.01) in partial correlations. PSA levels were higher in patients with prostate cancer (p<0.00001). Epitestosterone, which is negatively correlating with estradiol and IGF-1, may modulate the development of prostate diseases.     

Prostate cancer in elderly men

Due to increasing life expectancy and the introduction of prostate-specific antigen (PSA) screening, a rising number of elderly men are diagnosed with prostate cancer. Besides PSA serum levels and Gleason score, age is considered to be a key prognostic factor in terms of treatment decisions. In men older than 70 years, treatment without curative intent may deprive the frail patient of years of life. Modern radical prostatectomy techniques are associated with low perioperative morbidity, excellent clinical outcome, and documented long-term disease control. Thus, radical prostatectomy should be considered because local treatment of organ-confined prostate cancer potentially cures disease. The huge extent of PSA screening programs may lead to overdiagnosis of prostate cancer. Not every man who is diagnosed with prostate cancer will develop clinically significant disease. This has led to the concept of expectant management for screen-detected, small-volume, low-grade disease, with the intention of providing therapy for those men with disease progression.     

Prostate-specific antigen levels among cirrhotic patients

PURPOSE: The aim of this study was to determine serum prostate-specific antigen (PSA) levels in patients with liver cirrhosis. PATIENTS AND METHODS: Between January 1995 and August 2001, 216 men with cirrhosis were evaluated. The extent of their liver disease was classified according to the Child-Pugh classification. Serum PSA levels were measured with the Hybritech Tandem-R RIA method and matched with age-related reference PSA levels. Digital rectal examination (DRE) was performed in all patients. Patients with elevated PSA levels and/or abnormal DRE were recommended to undergo further assessment including transrectal ultrasonography (TRUS) and biopsy performed by an urologist. RESULTS: Two hundred and sixteen men (mean age 54.09 +/- 9.09 years, range 25-76) with cirrhosis were examined. Their mean PSA value was 0.57 +/- 0.84 ng/mL and tended to be lower than in the normal population. The degree of PSA decrease was found to parallel the severity of the liver disease (p=0.002). The mean serum PSA level increased with each age decade in a statistically significant manner (p<0.001). Four patients (three with elevated PSA values) underwent prostate biopsy. Three biopsies were positive for prostate cancer, the other showed evidence of benign prostatic hyperplasia (BPH). CONCLUSION: Serum PSA is influenced by the severity of liver disease and its levels tend to be lower in cirrhotic patients than in the normal population. However, serum PSA can still be considered a reliable marker in the clinical management of prostatic disease in patients with cirrhosis.     

Genetic variations in VDR associated with prostate cancer risk and progression in a Korean population

Low levels of vitamin D are implicated as a potential risk factor for prostate cancer, and the vitamin D receptor (VDR) gene may be important in the onset and progression of prostate cancer. In this study, sequence variants in the VDR gene were investigated in a Korean study cohort to determine whether they are associated with prostate cancer risk. We evaluated the association between 47 single nucleotide polymorphisms (SNPs) in the VDR gene and prostate cancer risk as well as clinical characteristics (prostate-specific antigen level, clinical stage, pathological stage and Gleason score) in Korean men (272 prostate cancer patients and 173 benign prostatic hyperplasia patient who underwent a prostate biopsy, which was negative for malignancy) using unconditional logistic regression. The statistical analysis suggested that two VDR sequence variants (rs2408876 and rs2239182) had a significant association with prostate cancer risk (odds ratio [OR]. 1.41; p = 0.03; OR, 0.73; p = 0.05, respectively). Logistic analyses of the VDR polymorphisms with several prostate cancer related factors showed that several SNPs were significant; nine SNPs to PSA level, three to clinical stage, two to pathological stage, and three SNPs to the Gleason score. The results suggest that some VDR gene polymorphisms in Korean men might not only be associated with prostate cancer risk but also significantly related to prostate cancer-related risk factors such as PSA level, tumor stage, and Gleason score. However, current limitation for small cohort with not-healthy control group might have false positive effects; therefore it should be overcome via further large-scale validating studies.     

Evaluation of specific antigen and prostatic acid phosphatase specificity. Study of false values

We assayed prostatic specific antigen (PSA) and prostatic acid phosphatase (PAP) serum levels in 1305 subjects without malignant prostatic pathology by double antibody RIA I125 to evaluate their specificity. When we set a second upper normal limit of 10 ng/ml for PSA and 2.5 ng/ml for PAP there was a significant increase of specificity. There were 2 and 3.7% false positive results in non-prostatic benign pathologies, 1.8 and 7.9% in non-prostatic malignant, 3.5 and 4.7% in non-complicated benign prostatic hypertrophy (BPH) and 3.3% for both in chronic prostatitis. In patients with complicated BPH and acute prostatitis the results were 64.8 and 24% for PSA and 20 and 16% for PAP. In conclusion, PSA is more specific than PAP in patients without acute inflammatory pathology of the prostate; the high rate of false positive values in the latter excludes its usefulness in these patients as diagnostic tumoral markers.     

An A/G polymorphism of core 2 branching enzyme gene is associated with prostate cancer

The expression of core 2 beta1,6-N-acetylglucosaminyltransferase-1 (C2GnT) is associated with development and progression of malignancy. Sequence analysis showed that the codon 152 of C2GnT has a polymorphism having GTT encoding valine or ATT encoding isoleucine. By examining the polymorphism in prostate cancer and benign prostatic hyperplasia patients, we found that the C2GnT G allele was more frequently observed in the prostate cancer group (p=0.015) than the control group. Men with the GG genotype had a 3.60-fold increased risk of prostate cancer, and men with the AG genotype had a 1.58-fold increased risk of prostate cancer compared with those with the AA genotype. The G allele was found to have a gene dosage effect for prostate cancer risk. No such risk was associated for benign prostatic hyperplasia. These results demonstrate that C2GnT A/G polymorphism is associated with the susceptibility to prostate cancer in a Japanese population.