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Query: UMLS:C0376358 (prostate cancer)
 59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Prostate specific antigen (PSA) has unequivocally proved its clinical usefulness ad a serum marker for prostate cancer. In order to enhance the specificity of serum PSA, several diagnostic parameters have been employed including PSA density of transition zone (TZ). The authors report their experience on the efficacy of PSA density TZ with level of PSA < 4 ng/ml, between 4-10 ng/ml, > 10 ng/ml, in the diagnostic of prostate cancer. The PSA density of TZ resulted uscless for PSA levels < 4 ng/ml, but improved the diagnostic specificity associated to PSA serum in the PSA levels ranging between 4-10 ng/ml and > 10 ng/ml.
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PMID:[Does PSA density of the transition zone represent a useful parameter in the diagnosis of prostate carcinoma?]. 1122 Oct 33

The screening programs for prostate cancer will affect a number increasing of patients over 50 years with consequence rising the bioptic demand. Nevertheless the istopathologic results are negatives for carcinoma in the most part of patients. It's evident that a part of carcinomas are lost at biopsy. Two hundred four patients where submitted at second bioptic session after a maximum of 12 months. Our results show a percent probability of positive findings in 12%. In 75% cancer diagnosed in that second session had clinically significance. Prostate specific antigen (PSA) value, in our study, is the most positive predictive parameter for prostate cancer at second biopsy. Patients with PSA > 10 ng/ml have a risk 7 times greater of having a prostatic cancer respect to patients with PSA < 10 ng/ml. PSA density, PSA velocity and the presence of ipoecoic areas previously biopsied, aren't risk factors for detection of prostate cancer at second bioptic session.
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PMID:[Repeated ultrasound-guided transrectal prostate biopsy in patients with negative histologic test]. 1122 Oct 36

Prostate specific antigen (PSA) is a protease which is characteristic of the prostate. It is widely used as a serum marker for the early diagnosis of prostate cancer (PCa). Nevertheless, for concentrations between 4 and 10 ng/mL, PSA does not enable PCa to be distinguished from benign diseases, such as benign prostate hyperplasia (BPH). In sera, the use of a ratio between free PSA (PSA uncomplexed with protease inhibitor) and total PSA (free PSA and PSA bound to alpha-1 anti-chymotrypsin) enables the "gray zone" to be reduced, but an important proportion of patients are still wrongly classed. Using two-dimensional electrophoresis, we demonstrated using 52 PCa and 40 BPH well-documented clinical cases that BPH sera show a significantly greater percentage of low-molecular-weight free PSA elements (IwPSA) than PCa sera. In our study, the use of a ratio between IwPSA and standard free PSA enables the correct diagnosis of 100% of PCa and 82.5% of BPH cases as against when 73.1% and 42.5% respectively were correctly diagnozed using the total PSA and the free/total PSA ratio. This important finding may be related to differences in the mechanism secreting PSA from the prostate into the bloodstream. We have shown how a tissue marker may be turned into a powerful tumor marker by events probably unrelated to its expression.
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PMID:Differential diagnosis of prostate cancer and benign prostate hyperplasia using two-dimensional electrophoresis. 1142 43

Prostate specific antigen (PSA) is a widely used marker for prostate cancer, which is secreted by normal prostate cells at low levels, but is produced more substantially by cancer cells. We have previously reported on the use of a DNA vaccine construct that encodes for human PSA gene to elicit host immune responses against cells producing PSA. DNA immunization strategy delivers DNA constructs encoding for a specific immunogen into the host, who becomes the in vivo protein source for the production of antigen. This antigen then is the focus of the resulting immune response. In this study, we examine the induction of immune responses and safety profiles in rhesus macaques immunized with DNA-based PSA vaccine. We observed induction of PSA-specific humoral response as well as positive PSA-specific lymphoproliferative (LPA) response in the vaccinated macaques. We also observed that the stimulated T cells from the PSA-immunized rhesus macaques produced higher levels of Th1 type cytokine IFN-gamma than the control vector immunized animals. On the other hand, DNA immunization did not result in any adverse effects in the immunized macaques, as indicated by complete blood counts, leukocyte differentials and hepatic and renal chemistries. The macaques appeared healthy, without any physical signs of toxicity throughout the observation period. In addition, we did not observe any adverse effect on the vaccination site. The apparent safety and immunogenecity of DNA immunization in this study suggest that further evaluation of this vaccination strategy is warranted.
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PMID:Induction of immune responses and safety profiles in rhesus macaques immunized with a DNA vaccine expressing human prostate specific antigen. 1149 45

Prostate specific antigen (PSA) has been proven to be a valuable tool in the diagnosis and staging of early prostate cancer and as a sensitive marker of residual or recurrent cancer after curative therapy. In 1998, 200 000 new cases of prostate cancer were reported in the SEER database. Two-thirds of these, or 134 000 men, underwent definitive therapy for localized cancer, including approximately 75 000 radical prostatectomies. It has been reported that 20%-50% of radical prostatectomy patients will have a PSA only recurrence. One can therefore estimate that every year 15 000 to 38 000 men will have a rising PSA following definitive surgical therapy. This elevation of PSA often precedes clinical failure by many years and poses a difficult management problem for which there are not, as yet, definitive management guidelines. This paper will review the definition of PSA recurrence, the natural history, diagnostic options and the therapeutic choices, as illustrated by several genuine cases.
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PMID:Rising prostate specific antigen after radical prostatectomy: a case based review. 1156 73

Prostate specific antigen (PSA) has been widely used as a tumor marker for screening, diagnosis and monitoring of prostate cancer. Use of PSA is very important for diagnosis during the primary screening for the early detection of prostate cancer. The presence of various PSA assays and with no uniform serum data have led to confusion among clinicians in the evaluation of serum data. The characteristics of each PSA assay, such as the equimolar or skewed type, must be taken into consideration at the time of use. For the early detection of prostate cancer, PSA density (PSAD), PSA adjusted for the transiton zone volume (PSATZ) and free to total PSA ratio may be useful in the selection of patients with intermediate PSA levels who should undergo prostate needle biopsy.
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PMID:[Prostate cancer]. 1168 Dec 60

Prostate specific antigen, the clinical marker for prostate cancer, is a neutral serine protease whose function is to lyse seminal proteins. Recent work by our laboratory has suggested that prostate specific antigen stimulates the generation of reactive oxygen species in prostate cancer cells. Using 2',7'-dichlorofluorescin diacetate, a dye that fluoresces in the presence of hydrogen peroxide or hydroxyl radicals, we found that prostate specific antigen markedly stimulated reactive oxygen species generation in LNCaP cells. The effect was concentration dependent and its specificity was supported by the fact that anti-prostate specific antigen antibodies abolished the response. Since testosterone stimulates the production of prostate specific antigen, we considered that the reactive oxygen species response to testosterone may be linked to prostate specific antigen. We found that the testosterone effect on reactive oxygen species was blocked by flutamide and by anti-prostate specific antigen antibody. Additionally, though PC3 and DU145 could not respond to testosterone, they readily increased reactive oxygen species in response to prostate specific antigen. Focusing on the mechanism of the prostate specific antigen effect, we tested two other serine proteases, trypsin and chymotrypsin, but found no effect on reactive oxygen species in LNCaP cells. Nevertheless, serine protease inhibitors, alpha(1)-antichymotrypsin, alpha(2)-macroglobulin and Bowman-Birk inhibitor, blocked reactive oxygen species generation stimulated by prostate specific antigen. This apparent paradox was investigated with the use of a specific anti-'prostate specific antigen' antibody which recognizes an epitope away from the catalytic site and which does not inhibit protease activity. Despite the lack of inhibition of proteolytic activity, this antibody blocked the effect of prostate specific antigen on reactive oxygen species generation. These findings suggest that although the integrity of the prostate specific antigen molecule is necessary for stimulating reactive oxygen species generation, its proteolytic activity is not. The underlying mechanism is currently under investigation.
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PMID:Testosterone and prostate specific antigen stimulate generation of reactive oxygen species in prostate cancer cells. 1169 38

Doxorubicin (Dox) can provide some stabilization in prostate cancer; however, its use is limited because of systemic toxicities, primarily cardiotoxicity and immunosuppression. The administration of a prodrug of doxorubicin, designed to permit selective activation by the tumor, would reduce general systemic exposure to the active drug and would thereby increase the therapeutic index. Prostate specific antigen (PSA) is a serine protease with chymotrypsin-like activity that is a member of the kallikrein gene family. PSA's putative physiological role is the liquefaction of semen by virtue of its ability to cleave the seminal fluid proteins semenogelins I and II. Serum PSA levels have been found to correlate well with the number of malignant prostate cells. The use of a prodrug which is cleaved by the enzyme PSA in the prostate should in principle produce high localized concentrations of the cytotoxic agent at the tumor site while limiting systemic exposure to the active drug. Cleavage maps following PSA treatment of human semenogelin were constructed. Systematic modification of the amino acid residues flanking the primary cleavage site led to the synthesis of a series of short peptides which were efficiently hydrolyzed by PSA. Subsequent coupling of selected peptides to doxorubicin provided a series of doxorubicin-peptide conjugates which were evaluated in vitro and in vivo as targeted prodrugs for PSA-secreting tumor cells. From these studies we selected Glutaryl-Hyp-Ala-Ser-Chg-Gln-Ser-Leu-Dox, 27, as the peptide-doxorubicin conjugate with the best profile of physical and biological properties. Compound 27 has a greater than 20-fold selectivity against human prostate PSA-secreting LNCaP cells relative to the non-PSA-secreting DuPRO cell line. In nude mouse xenograft studies, 27 reduced PSA levels by 95% and tumor weight by 87% at a dose below its MTD. Both doxorubicin and Leu-Dox (13) were ineffective in reducing circulating PSA and tumor burden at their maximum tolerated doses. On the basis of these results, we selected 27 for further study to assess its ability to inhibit human prostate cancer cell growth and tumorigenesis.
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PMID:The synthesis of a prodrug of doxorubicin designed to provide reduced systemic toxicity and greater target efficacy. 1170 23

Prostate specific antigen (PSA) is the marker of choice in the management of prostate cancer. However, PSA is not a simple molecule, existing in the serum in five isoforms and a number of molecular configurations and complexes. The elucidation of the biochemistry of PSA has increased the potential use of the marker in the diagnosis of prostate malignancy. This review summarizes the clinical use of PSA in the management of prostate disease and the assays available in the UK. Assay calibration in relation to the World Health Organization 1st International Standard for Prostate Specific Antigen (90:10) has increased conformity between the various commercial assay kits, and the non-equimolar kits have largely been superseded or withdrawn. Special reference is made to evaluations performed on behalf of the Medical Devices Agency of the Department of Health.
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PMID:Prostate specific antigen: biology, biochemistry and available commercial assays. 1173 46

Prostate cancer is one of the leading causes of cancer-related death among men. Given the varying clinical course and the long natural history of the disease, it is important to have good diagnostic and prognostic markers. Prostate specific antigen (PSA) is currently the best marker for the detection of prostate cancer, but in many cases it does not reveal whether metastases have appeared. Since metastases of prostate cancer release prostasomes, which are immunogenic secretory granules of both normal and neoplastic prostate cells, we checked whether anti-prostasome antibodies will appear when the cancer is metastasing. In a pilot study, all 13 patients with serum PSA between 50-500 microg/L had anti-prostasome antibodies, while 39 healthy controls with low PSA values showed background values. There was no overlapping, i.e. the upper range value of controls did not reach the lower range value of patients.
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PMID:Autoantibodies to prostasomes as new markers for prostate cancer. 1181 62


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