The role of the detection of hematogenous micrometastasis in prostate adenocarcinoma and malignant melanoma by RT-PCR

Recent studies reported the possibility of detecting prostate adenocarcinoma and malignant melanoma cells in peripheral blood using RT-PCR of prostatic specific antigen (PSA), prostatic specific membrane antigen (PSMA) and Tyrosinase mRNAs. The PCR results showed high variability, ranging between 0% and 100% of positivity in patients with advanced disease. Our purpose was to evaluate the presence of tumor marker mRNAs in peripheral blood of prostate cancer and melanoma patients by means of RT-nested-PCR. We tested 70 and 36 peripheral blood samples from prostate carcinoma and malignant melanoma patients, respectively. The RT-PCR analysis showed the presence of PSA cDNA in 9 out of 70 (12.9%); PSMA cDNA in 14 out of 70 (20%); and Tyrosinase cDNA in 2 out of 36 (5.5%) peripheral blood samples from melanoma patients. Our study confirms the applicability of this sensitive method to monitor disease status. Although, the RT-nested-PCR of Tyrosinase is able to detect neoplastic cells in peripheral blood specimens, we suggest the necessity of a great caution in interpreting PCR results when the nested method has been used.     

Correlation between CD8+ T cells specific for prostate-specific antigen and level of disease in patients with prostate cancer

Modest work has been performed to improve the sensitivity of residual disease detection or investigate the contribution that the immune system makes in controlling metastatic tumor growth, in particular, the frequency and biological actions of peptide-specific CD8+ T lymphocytes in limiting metastatic disease and/or maintaining remission. Fifty-three peripheral blood samples from 32 prostate cancer (PC) patients were investigated for the presence of circulating prostate-specific antigen (PSA)-expressing cells (CPECs) using a highly sensitive and specific assay combining immunomagnetic epithelial cell enrichment with nested RT-PCR of PSA mRNA. Using HLA-A2 tetramer complexes, frequency of CD8+ T cells specific for PSA-derived peptides was determined. Additionally, serum concentrations of PSA and testosterone were measured. CPECs were detected in 26% of peripheral blood samples from PC patients. CD8+ T cells specific for PSA-derived peptides were detected at low frequency in HLA-A2-positive PC patients. The correlation between these PSA-specific CD8+ T cells and residual prostate tumor cells and clinical measures was investigated. Our data suggest that frequency of PSA-specific CD8+ T cells is correlated to CPECs, but not to serum PSA level.     

PSA-PSMA profiles and their impact on sera PSA levels and angiogenic activity in hyperplasia and human prostate cancer

Aim

The relevance of prostate specific antigen (PSA)-prostate specific membrane antigen (PSMA) profiles in pathologic prostate (hyperplasia and cancer) has not been fully understood. The aim of this study is to investigate the impact of PSA-PSMA profiles on sera PSA levels and angiogenic activity in benign prostate hyperplasia (BPH) and prostate carcinoma (PC).

Patients and methods

The study has been carried out in 6 normal prostate (NP), 29 BPH and 33 PC with dominant Gleason grade > 8. Immunohistochemical analysis has been performed. Monoclonal antibodies 3E6 and ER-PR8 have been used to assess PSMA and PSA expression respectively. The evaluation of angiogenesis has been made by CD34 immune marker. Serum levels of PSA have been assayed by Immulite autoanalyser.

Results

The study of each protein separately among sera PSA levels showed that PSMA expression and angiogenic activity have the highest intensity in PC patients with serum PSA levels > 20 ng/mL. Nevertheless, the lowest tissue PSA expression was found in PC patients with this latter sera PSA group. The most relevant results showed that in PC patients (PSA+, PSMA+) and (PSA–, PSMA+) profile were found to be inversely related to sera PSA levels. In PC patients, a high immunoexpression of (PSA+, PSMA+) profile has detected in the sera PSA group > 20 ng/mL; whereas a high immunoexpression of (PSA–, PSMA+) profile was detected in the sera PSA group between 0 and 4 ng/mL. The highest angiogenic activity was found in PC patients with (PSA+, PSMA+) profile.

Conclusions

Our findings clearly have supported the feasibility of PSA-PSMA profiles to improve in vivo diagnostic and therapeutic approaches in prostate cancer patients.     

Squamous metaplasia of the prostate. An immunohistochemical study

Immunoperoxidase strains for prostate-specific antigen (PSA), prostatic acid phosphatase (PAcP), epithelial membrane antigen (EMA), and cytokeratins (MAK 6 and CK-KES) were performed on 1 case of squamous cell carcinoma of the prostate and on 13 cases of squamous metaplasia of prostatic epithelium in an effort to demonstrate prostatic origin of the neoplastic and metaplastic cells and to differentiate them from primary or metastatic well-differentiated squamous cell carcinoma. The authors found no specific staining of the metaplastic or neoplastic cells for PSA and only focal single cell PAcP positivity in three cases of squamous metaplasia. All cases showed strong staining of surrounding normal glandular epithelium for both antigens. In all but one case, both the metaplastic and glandular epithelium had positive results for MAK 6 and CK-KES. EMA was expressed strongly in ten cases, was weak or variable in two, and had negative results in two cases of squamous metaplasia. In only four cases did the glandular epithelium have positive results for EMA. The remaining cases showed no staining. PSA and PAcP marking, therefore, may not be useful for separating atypical squamous metaplasia from well-differentiated squamous cell carcinoma or even primary prostatic from metastatic squamous cell carcinoma. These findings suggest that although prostatic glandular epithelial cells retain their ability to express some prostate-associated antigens, this ability is greatly reduced, lost, or not developed in cells that undergo metaplasia into squamous cells or that develop into squamous cell carcinoma.     

The utility of PSMA and PSA immunohistochemistry in the cytologic diagnosis of metastatic prostate carcinoma

The diagnosis of metastatic prostate carcinoma frequently requires the use of immunohistochemical adjuncts. Immunohistochemistry for prostate‐specific antigen (PSA) is commonly used for this purpose but can be of limited utility. Recently, prostate‐specific membrane antigen (PSMA) has been shown to be a promising marker for the identification of metastatic prostate carcinoma in surgical specimens. The utility of this marker has yet to be reported for cytology specimens. We sought to compare the sensitivities of PSMA and PSA immunohistochemistry and investigate the specificity of PSMA by utilizing cell block preparations from cytologic cases of metastatic prostate carcinoma (n = 19) and carcinomas of nonprostatic origin (n = 33). The sensitivity of PSMA immunohistochemistry was higher (16/19; 84%) in detecting metastatic prostate carcinomas than that of PSA immunohistochemistry (11/19; 58%). Strong, diffuse staining for PSMA was seen in 13 (81%) of 16 PSMA‐positive cases whereas strong, diffuse staining for PSA was observed in six (55%) of 11 PSA‐positive cases. Positivity for either PSMA or PSA was seen in 17 of 19 cases of metastatic prostate carcinoma for a combined sensitivity of 89%. PSMA immunohistochemistry was completely negative in 32 of 33 cytology cases of nonprostatic carcinomas. Therefore, the specificity of this marker was 97% in this study. In conclusion, our results indicate that PSMA is a highly sensitive and specific immunomarker for the detection of metastatic prostate carcinoma in cytology specimens. Diagn. Cytopathol. 2014;42:570–575. © 2013 Wiley Periodicals, Inc.     

新型前列腺特异膜抗原剪接变异体的发现及临床意义初步探讨

目的:探讨前列腺特异膜抗原（PSMA）及其与前列腺癌发生、发展的关系，寻求更为特异的前列腺癌诊断和治疗的靶点。 方法:采用RT-PCR和DNA测序技术，克隆PSMA基因新的剪接变异体，并根据其序列信息，设计特异性引物，检测其在不同病变前列腺组织及不同组织来源肿瘤细胞中的表达。 结果:发现了一种新的PSMA剪接变异体，其在前列腺癌、前列腺增生及正常前列腺组织中的表达率分别为92.6％、78.8％及10.0％，且特异表达于前列腺癌LNCaP细胞株，而在前列腺癌PC3细胞株、膀胱癌、肾癌、肝癌细胞株中均不表达。 结论:发现了一种新型PSMA剪接变异体（定名为PSMA5），并证实该变异体与前列腺癌及前列腺增生有明显相关性，为研究前列腺癌的发生机制和寻求前列腺癌特异性诊治靶点提供了新的线索。     

111In-Capromab Pendetide

Each year, approximately 210 000 American men are diagnosed with prostate cancer and 41 800 die from the disease - numbers roughly equal to the incidence and mortality for breast cancer in women. Prostate cancer usually shows no symptoms in early stages, when it is most treatable. To detect the disease early, physicians usually recommend that every man 50 years and older have an annual examination consisting of a digital rectal examination and a prostate specific antigen (PSA) blood test. Conventional treatments such as surgical removal of the diseased prostate, external beam radiation, radioactive seed therapy and hormonal and/or chemotherapy treatment regimens are most successful for early stage prostate cancer and have limited effectiveness in advanced stages of the disease. For this reason, accurate staging of primary and recurrent prostate cancer is mandatory for proper therapeutic decisions. Nuclear medicine imaging of prostate cancer using the radiolabelled monoclonal antibody, (111)In-capromab pendetide, has proven useful in newly diagnosed patients with biopsy-proven prostate cancer in which there is high suspicion of distant metastatic disease and for prostatectomy patients with rising PSA levels and/or suspicion of recurrence or metastatic disease. Although not intended as a screening tool, it is used in conjunction with standard evaluation procedures for improved staging of patients. The monoclonal antibody, designated 7E11-C5, binds the prostate specific membrane antigen (PSMA) expressed on the surface of prostate epithelial cells and up-regulated in tumour cells. The sensitivity and specificity for prostate cancer involved lymph node detection has been reported as 62 to 75% and 72 to 86%, respectively, compared with sensitivities of 4% and 15% for computerised tomography and magnetic resonance imaging. (111)In-capromab pendetide imaging has proven to be an accurate, non-invasive tool for detecting and staging sites of recurrence in the post-prostatectomy patient as well as metastatic sites in the patient with newly diagnosed prostate cancer.     

Immunohistochemical study of the prostate-specific antigen in prostatic cancer

Prostate-specific antigen (PSA) is secreted both by normal epithelial prostatic cells and cell of prostatic carcinoma (PC). No parallelism exists between the degree of PC differentiation and the type of PSA secretion. PSA concentration in the peripheral blood not always corresponds to the intensity of its immunoreactivity on the tissue level. Amount of PSA in the blood depends on the stroma vascularisation and number of cells contacting with the organ stroma. A decrease of PSA in the peripheral blood due to therapy may be combined with high intensity of its synthesis in tumor cells. PSA immunohistochemistry may be recommended as a method of PC clinical course monitoring and dynamics of its changes in the course of carcinoma therapy.     

Prostate-specific membrane antigen expression as a predictor of prostate cancer progression

Distinguishing aggressive prostate cancer from indolent disease represents an important clinical challenge, because current therapy may lead to overtreatment of men with limited disease. The prostate-specific membrane antigen (PSMA) is a membrane-bound glycoprotein that is highly restricted to the prostate. Previously, studies analyzing the expression of PSMA have found an up-regulation in correlation with prostate cancer, particularly in advanced cancer. This association is ideal for an application as a prognostic marker. In the current study, we characterized PSMA expression in a high-risk cohort and evaluated its potential use as predictive marker of prostate-specific antigen (PSA) recurrence. PSMA expression was analyzed by immunohistochemistry using tissue microarrays composed of tumor samples from 450 patients. Protein intensity was recorded using a semiautomated quantitative microscope system (ACIS II; Clarient Chromavision Medical Systems, San Juan Capistrano, CA). PSMA expression levels differed significantly (P < .001) between benign prostatic tissue, localized prostate cancer, and lymph node metastases. Dividing the cohort into high- and low-PSMA expressing cancers based on the median area of positive staining, we found that high PSMA levels were associated with significant increase of PSA recurrence (P = .004). This was independent of clinical parameters such as lymph node tumor burden (lymph node density, >20%; P < .001), extraprostatic extension (P = .017), seminal vesicle invasion (P < .001), and high Gleason score (8-10, P = .006). In a multivariate model, PSMA expression and metastases to pelvic lymph nodes were significantly associated with time to PSA recurrence (HR, 1.4; 95% confidence interval, 1.1-2.8, P = .017; and hazard ratio, 5; 95% confidence interval, 2.6-9.7, P < .001, respectively). In summary, PSMA is independently associated with PSA recurrence in a high-risk cohort and thus might provide insight into the additional use of adjuvant therapy. Validation on other cohorts is required.     

Vascular endothelial growth factor in patients with prostate cancer and benign prostatic hyperplasia

The authors examined 25 patients with prostate cancer (PC) and 36 patients with benign prostatic hyperplasia (BPH). In the group of patients with morphologically verified PC mean serum level of vascular endothelial growth factor (VEGF) was significantly higher than in patients with BPH (p < 0.05). The study demonstrated strong negative association between VEGF and prostate specific antigen (PSA) levels (r = 0.72, p < 0.05) in PC patients. There was no association between VEGF serum level and the stage or malignancy of PC (Gleason score). In benign prostatic glands moderate VEGF expression was observed only in basal cells, whereas in cases of PC all tumor cells displayed active VEGF expression; the difference was significant (p < 0.05). High serum VEGF levels and its active expression in patients with PC suggest an important role of angiogenic factors in the pathogenesis of this disease. The negative association between VEGF and PSA serum levels in PC indirectly confirms antiangiogenic activity of PSA, shown before.     

Correlation between PSMA and VEGF expression as markers for LNCaP tumor angiogenesis

Our aim is the identification and correlation of changes in tumor-associated protein expression which results from therapy. LNCaP tumors, excised from nude mice treated either by orchiectomy or with the chemotherapeutic agent paclitaxel, were evaluated for the expression of proteins and receptors associated with growth, differentiation, and angiogenesis using immunohistologic procedures. Compared to untreated control tumors, both treatments reduced the expression of vascular endothelial growth factor (VEGF), prostate-specific membrane antigen (PSMA), prostate-specific antigen (PSA), androgen receptor (AR), and epidermal growth factor receptor (EGFR). The effect of paclitaxel treatment on AR expression was the most significant (P = .005). Of particular interest was identifying a significant correlation (P < .000801) between PSMA and VEGF expression regardless of treatment modality. These altered expressions suggest that PSMA may also be a marker for angiogenesis and could represent a target for deliverable agents recognizing either prostatic tumors or endothelial development. Cell surface PSMA would then present a unique target for treatment of patients early in their development of prostatic metastases.     

Coordinate expression of cytokeratins 7 and 20 in prostate adenocarcinoma and bladder urothelial carcinoma

We studied the expression of cytokeratin (CK)-7 and CK-20 in prostate adenocarcinoma and urothelial carcinoma and evaluated their usefulness for distinguishing high-grade forms of these tumors. We examined prostate adenocarcinoma in 59 radical prostatectomy specimens and in 10 autopsy specimens showing metastatic disease, and urothelial carcinoma of the bladder in 28 cystectomy specimens. Immunohistochemical staining for CK-7, CK-20, and prostate-specific antigen (PSA) was performed on paraffin sections. For prostate adenocarcinoma, 5 cases had only CK-7 positivity, 5 had only CK-20 focal positivity, 1 stained for both markers, and 48 were negative for both. PSA was positive in all but 1 poorly differentiated prostatic carcinoma. In the autopsy cases, PSA was expressed in the prostate and the metastatic tumors in most cases; few cases were focally positive for CK-7 or CK-20, but none was positive for both markers. For the urothelial tumors, CK-7 was the sole positive marker in 6 cases, and CK-20 in 1 case; 17 cases were positive for both, and 4 were negative for both. All urothelial carcinomas were PSA negative. Although PSA is useful for differentiating prostatic from urothelial carcinoma, CK-7 and CK-20 are helpful when both are positive, supporting the diagnosis of urothelial carcinoma. However, if only 1 marker is positive or both are negative, these markers have limited usefulness for distinguishing these carcinomas.     

A quantitative model for the dynamics of serum prostate-specific antigen as a marker for cancerous growth: an explanation for a medical anomaly

Prostate-specific antigen (PSA) is an enzyme produced by both normal and cancerous prostate epithelial cells. Although PSA is the most widely used serum marker to detect and follow patients with prostatic adenocarcinoma, there are certain anomalies in the values of serum levels of PSA that are not understood. We developed a mathematical model for the dynamics of serum levels of PSA as a function of the tumor volume. Our model results show good agreement with experimental observations and provide an explanation for the existence of significant prostatic tumor mass despite a low-serum PSA. This result can be very useful in enhancing the use of serum PSA levels as a marker for cancer growth.     

Expression of prostate specific antigen in male breast cancer

Male breast cancer is uncommon, accounting for less than 1% of all breast cancers. Carcinoma metastatic to the male breast is also unusual, with metastatic prostatic carcinoma being among the most common primary sites from which such tumours derive. Metastatic prostatic cancer and primary breast cancer may be histologically indistinguishable without immunohistochemistry because both often infiltrate with a cribriform architecture. Distinguishing between primary and metastatic disease within the breast is important because the treatment options for each are radically different. Following a case in which metastatic prostatic disease was initially wrongly diagnosed as primary breast cancer, a small series of male breast cancers was examined for expression of prostate specific antigen (PSA) and prostatic acid phosphatase to assess the usefulness of these markers in making this distinction. Focal expression of PSA was found in one of 11 cases of male breast cancer. These results indicate that PSA should be used with caution in this context.     

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.     

BPH-1通过分泌前列腺素E2促进前列腺间质细胞芳香化酶的表达

目的：研究前列腺上皮细胞旁分泌对间质细胞芳香化酶表达的影响。方法：用前列腺上皮细胞系（BPH-1, LNCap, DU145, PC3）条件培养液（CM）处理间质细胞，用RT-qPCR和Western blotting检测芳香化酶表达水平。用RT-qPCR和ELISA检测上皮细胞系环氧合酶2（COX-2）的表达及其CM前列腺素E2(PGE2)浓度。用添加COX-2特异性抑制剂NS-398的培养液培养BPH-1，检测其CM和PGE2对间质细胞芳香化酶表达影响。结果：良性前列腺增生上皮细胞系BPH-1 CM能促进间质细胞芳香化酶mRNA和蛋白的表达，而前列腺癌细胞系PC3、DU-145和LNCap对芳香化酶的表达没有影响。BPH-1 COX-2 mRNA表达水平和PGE2分泌水平远高于其它癌细胞系。添加NS-398培养BPH-1的CM，其PGE2浓度明显降低。PGE2可明显诱导间质细胞芳香化酶的表达。结论：BPH-1通过分泌PGE2促进前列腺间质细胞芳香化酶的表达。     

Prostate-specific antigen-positive extramammary Paget's disease--association with prostate cancer

Extramammary Paget's disease (EMPD) is a rare intraepidermal adenocarcinoma that primarily affects the anogenital region. Cases of EMPD reacting with PSA (prostate-specific antigen) have previously been associated with underlying prostate cancer. However, a recent case of EMPD in our department has led us to question the value of PSA as an indicator of underlying prostate cancer. Clinical and pathological data were obtained for 16 cases of EMPD. Formalin-fixed, paraffin-embedded tissue blocks from the primary skin lesions were investigated using PSA and other immunohistochemical markers. 5 of the 16 cases of EMPD stained positive for PSA (2 women and 3 men). However, no reactivity was seen for the prostatic marker P501S. Three of the five patients had been diagnosed with internal malignant disease-two with prostate cancer, stage 1. Immunohistochemical investigations of the tumour specimens from the prostate revealed an immunoprofile which was very different from that of the primary skin lesion. In our study, no cases of EMPD with PSA positivity seem to represent an extension of an underlying prostatic adenocarcinoma. PSA positivity can be seen in cases of EMPD without associated adenocarcinoma of the prostate.     

Serum prostate-specific antigen and prostate pathology in men having simple prostatectomy

Prostate-specific antigen (PSA) is a sensitive and specific serum marker for monitoring disease activity in men with prostatic carcinoma. Despite reports of elevation of levels of this analyte in men with benign prostatic hyperplasia, no information is available correlating the serum levels with the actual prostatic abnormalities in men having prostatectomy for presumed benign disease. In the present investigation, the authors compared preoperative serum PSA levels with prostate disease in 81 men with bladder outlet obstruction. Five pathologic groups were found: incidental high-grade carcinoma (n = 3), low-grade carcinoma (n = 11), acute inflammation (n = 16) with or without chronic inflammation, Prostatic intraepithelial neoplasia (PIN) (n = 25), and benign hyperplasia (n = 26). Serum PSA levels were significantly elevated in both low- and high-grade carcinoma, acute inflammation, and PIN when compared with the patients with benign hyperplasia with and without chronic inflammation. Within the four groups with elevated levels, use of PSA levels could separate only the high-grade cancer patients who were subsequently shown to have metastatic disease. Only one patient with simple hyperplasia had PSA levels in the abnormal range.