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

Kinetic Analysis of Prostate-Specific Antigen Interaction with Monoclonal Antibodies for Development of a Magnetic Immunoassay Based on Nontransparent Fiber Structures

Prostate cancer is the second most common cancer diagnosed in men worldwide. Measuring the prostate-specific antigen (PSA) is regarded as essential during prostate cancer screening. Early diagnosis of this disease relapse after radical prostatectomy requires extremely sensitive methods. This research presents an approach to development of an ultrasensitive magnetic sandwich immunoassay, which demonstrates the limit of PSA detection in human serum of 19 pg/mL at a dynamic range exceeding 3.5 orders of concentration. Such attractive performance stems, inter alia, from the kinetic analysis of monoclonal antibodies (mAbs) against free PSA to select the mAbs exhibiting best kinetic characteristics and specificity. The analysis is carried out with a label-free multiplex spectral-correlation interferometry compatible with inexpensive single-use glass sensor chips. The high sensitivity of developed PSA immunoassay is due to electronic quantification of magnetic nanolabels functionalized by the selected mAbs and three-dimension porous filters used as an extended solid phase. The assay is promising for PSA monitoring after radical prostatectomy. The proposed versatile approach can be applied for the rational design of highly sensitive tests for detection of other analytes in many fields, including in vitro diagnostics, veterinary, food safety, etc.

Exome sequencing identifies RASSF1 and KLK3 germline variants in an Iranian multiple-case breast cancer family

Breast cancer is the most frequent malignancy among women in both developed and developing countries. Although several genes have been identified to harbor germline variants contributing to breast cancer risk, much of the heritability for breast cancer is yet undefined. In the present study, we have performed exome sequencing to detect susceptibility genes in an Iranian family with five first-degree family members affected with breast cancer. We identified novel candidate variants with predicted pathogenicity in RASSF1, KLK3 and FAM81B. The RASSF1 and KLK3 variants, but not the FAM81B variant, partially co-segregated with disease in the investigated pedigree and were not found in additional screenings outside the specific family. RASSF1 p.S135F is a missense substitution abolishing the ATM phosphorylation site, and KLK3 variant p.M1? is a deletion at the initiation codon that is predicted to abolish translation to the functional kallikrein protease, PSA. Our study suggests germline variation in RASSF1 and KLK3 as candidate contributors to familial breast cancer predisposition and illustrates the difficulties to determine the causal genetic risk factor among novel variants restricted to a single family.

Secreted indicators of androgen receptor activity in breast cancer pre-clinical models

PURPOSE

Accumulating evidence has attracted attention to the androgen receptor (AR) as a biomarker and therapeutic target in breast cancer. We hypothesized that AR activity within the tumor has clinical implications and investigated whether androgen responsive serum factors might serve as a minimally invasive indicator of tumor AR activity.

METHODS

Based on a comprehensive gene expression analysis of an AR-positive, triple negative breast cancer patient-derived xenograft (PDX) model, 163 dihydrotestosterone (DHT)-responsive genes were defined as an androgen responsive gene set. Among them, we focused on genes that were DHT-responsive that encode secreted proteins, namely KLK3, AZGP1 and PIP, that encode the secreted factors prostate specific antigen (PSA), zinc-alpha-2-glycoprotein (ZAG) and prolactin induced protein (PIP), respectively. Using AR-positive breast cancer cell lines representing all breast cancer subtypes, expression of candidate factors was assessed in response to agonist DHT and antagonist enzalutamide. Gene set enrichment analysis (GSEA) was performed on publically available gene expression datasets from breast cancer patients to analyze the relationship between genes encoding the secreted factors and other androgen responsive gene sets in each breast cancer subtype.

RESULTS

Anti-androgen treatment decreased proliferation in all cell lines tested representing various tumor subtypes. Expression of the secreted factors was regulated by AR activation in the majority of breast cancer cell lines. In GSEA, the candidate genes were positively correlated with an androgen responsive gene set across breast cancer subtypes.

CONCLUSION

KLK3, AZGP1 and PIP are AR regulated and reflect tumor AR activity. Further investigations are needed to examine the potential efficacy of these factors as serum biomarkers.

Plasma level of prostate related-antigen peptide-reactive IgG is a prognostic factor of patients with breast cancer treated with personalized peptide vaccines

The present study assessed plasma IgG in patients with metastatic recurrent breast cancer (mrBC) that is reactive to various T-cell epitope peptides of prostate-related antigens (PRAs), such as prostate-specific antigen, prostate-specific membrane antigen and prostate acid phosphatase. Patients were treated with personalized peptide vaccines (PPVs) which were selected and administered from a panel of candidate peptides based on human leukocyte antigen-types and prevaccination IgG levels to each peptide. The peptide panel consisted of 27 cytotoxic T-lymphocyte-epitope peptides derived from tumor-associated antigens, not including PRA. PRA peptides and peptide panels were retrospectively analyzed in 77 PPV-treated patients. The results revealed that PRA reactive IgG levels were increased after vaccination in 31 of the 97 patients included in the present study. Although there was no significant association between anti-PRA peptide levels and progression-free survival (PFS) or overall survival, anti-PRA peptide levels were significantly associated with PFS (P=0.009) in estrogen-receptor positive (ER+) patients with cancer. The results suggested that plasma anti-PRA IgG levels may be a useful prognostic marker for monitoring PPVs, particularly for ER+ patients with mrBC (trial registration no. from the UMIN Clinical Trials Registry, UMIN000001844).

A Phenomic Perspective on Factors Influencing Breast Cancer Treatment: Integrating Aging and Lifestyle in Blood and Tissue Biomarker Profiling

Breast cancer is the most common malignancy among women worldwide. Over the last four decades, diagnostic and therapeutic procedures have improved substantially, giving patients with localized disease a better chance of cure, and those with more advanced cancer, longer periods of disease control and survival. However, understanding and managing heterogeneity in the clinical response exhibited by patients remains a challenge. For some treatments, biomarkers are available to inform therapeutic options, assess pathological response and predict clinical outcomes. Nevertheless, some measurements are not employed universally and lack sensitivity and specificity, which might be influenced by tissue-specific alterations associated with aging and lifestyle. The first part of this article summarizes available and emerging biomarkers for clinical use, such as measurements that can be made in tumor biopsies or blood samples, including so-called liquid biopsies. The second part of this article outlines underappreciated factors that could influence the interpretation of these clinical measurements and affect treatment outcomes. For example, it has been shown that both adiposity and physical activity can modify the characteristics of tumors and surrounding tissues. In addition, evidence shows that inflammaging and immunosenescence interact with treatment and clinical outcomes and could be considered prognostic and predictive factors independently. In summary, changes to blood and tissues that reflect aging and patient characteristics, including lifestyle, are not commonly considered clinically or in research, either for practical reasons or because the supporting evidence base is developing. Thus, an aim of this article is to encourage an integrative phenomic approach in oncology research and clinical management.

Association Between Serum Testosterone and Serum PSA Among Men With and Without Partial Androgen Deficiency

Serum prostatic specific antigen (PSA) and serum testosterone levels share an undefined relationship with each other, with many conflicting studies showing both positive and negative correlation between them. Our aim was to assess association between serum PSA and serum testosterone in healthy men with normal testosterone levels and men with partial androgen deficiency (PADAM). A cross sectional study was conducted at a teaching hospital setting where serum testosterone and aging male symptom scale (AMS) scores along with PSA were studied in 255 men (> 50 years) with and without PADAM. Mean total testosterone and serum PSA was 9.35 ± 1.33 nmol/L, 1.96 ± 0.76 ng/mL in males with PADAM and 15.30 ± 1.95 nmol/L, 1.85 ± 0.73 ng/mL respectively in males without PADAM. No significant relationship was observed between serum PSA and serum testosterone levels among healthy males irrespective of PADAM in the study population. We suggest, there is no need to adjust PSA values for biopsy decisions according to testosterone levels.

Harnessing Androgen Receptor Pathway Activation for Targeted Alpha Particle Radioimmunotherapy of Breast Cancer

PURPOSE

The impact of androgen receptor (AR) activity in breast cancer biology is unclear. We characterized and tested a novel therapy to an AR-governed target in breast cancer.Experimental Design: We evaluated the expression of prototypical AR gene products human kallikrein 2 (hK2) and PSA in breast cancer models. We screened 13 well-characterized breast cancer cell lines for hK2 and PSA production upon in vitro hormone stimulation by testosterone [dihydrotestosterone (DHT)]. AR-positive lines were further evaluated by exposure to estrogen (17β-Estradiol) and the synthetic progestin D-Norgestrel. We then evaluated an anti-hK2-targeted radiotherapy platform (hu11B6), labeled with alpha (α)-particle emitting Actinium-225, to specifically treat AR-expressing breast cancer xenografts under hormone stimulation.

RESULTS

D-Norgestrel and DHT activated the AR pathway, while 17β-Estradiol did not. Competitive binding for AR protein showed similar affinity between DHT and D-Norgestrel, indicating direct AR-ligand interaction. In vivo production of hK2 was sufficient to achieve site-specific delivery of therapeutic radionuclide to tumor tissue at >20-fold over background muscle uptake; effecting long-term local tumor control.

CONCLUSIONS

[²²⁵Ac]hu11B6 targeted radiotherapy was potentiated by DHT and by D-Norgestrel in murine xenograft models of breast cancer. AR activity in breast cancer correlates with kallikrein-related peptidase-2 and can be activated by D-Norgestrel, a common contraceptive, and AR induction can be harnessed for hK2-targeted breast cancer α-emitter radiotherapy.

New Biomarkers to Evaluate Hyperandrogenemic Women and Hypogonadal Men

Androgens can have variable effects on men and women. Women may be evaluated for androgen excess for several reasons. Typically, young premenopausal women present with clinical symptoms of hirsutism, alopecia, irregular menses, and/or infertility. The most common cause of these symptoms is polycystic ovary syndrome. After menopause, even though ovaries stop producing estrogen, they continue to produce androgen, and women can have new onset of hirsutism and alopecia. Laboratory evaluation involves measurement of the major ovarian and adrenal androgens. In women, age, phase of the menstrual cycle, menopausal status, obesity, metabolic health, and sex hormone-binding proteins significantly affect total-androgen levels and complicate interpretation. This review will summarize the clinically relevant evaluation of hyperandrogenemia at different life stages in women and highlight pitfalls associated with interpretation of commonly used hormone measurements. Hypogonadism in men is a clinical syndrome characterized by low testosterone and/or low sperm count. Symptoms of hypogonadism include decreased libido, erectile dysfunction, decreased vitality, decreased muscle mass, increased adiposity, depressed mood, osteopenia, and osteoporosis. Hypogonadism is a common disorder in aging men. Hypogonadism is observed rarely in young boys and adolescent men. Based on the defects in testes, hypothalamus, and/or pituitary glands, hypogonadism can be broadly classified as primary, secondary, and mixed hypogonadism. Diagnosis of hypogonadism in men is based on symptoms and laboratory measurement. Biomarkers in use/development for hypogonadism are classified as hormonal, Leydig and Sertoli cell function, semen, genetic/RNA, metabolic, microbiome, and muscle mass-related. These biomarkers are useful for diagnosis of hypogonadism, determination of the type of hypogonadism, identification of the underlying causes, and therapeutic assessment. Measurement of serum testosterone is usually the most important single diagnostic test for male hypogonadism. Patients with primary hypogonadism have low testosterone and increased luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Patients with secondary hypogonadism have low testosterone and low or inappropriately normal LH and FSH. This review provides an overview of hypogonadism in men and a detailed discussion of biomarkers currently in use and in development for diagnosis thereof.

Serum complexed and free prostate-specific antigen (PSA) for the diagnosis of the polycystic ovarian syndrome (PCOS)

BACKGROUND

Polycystic ovarian syndrome (PCOS) is a common cause of reproductive and metabolic dysfunction. We hypothesized that serum prostate-specific antigen (PSA) may constitute a new biomarker for hyperandrogenism in PCOS.

METHODS

We conducted a cross-sectional study of 45 women with PCOS and 40 controls. Serum from these women was analyzed for androgenic steroids and for complexed PSA (cPSA) and free PSA (fPSA) with a novel fifth- generation assay with a sensitivity of ~10 fg/mL for cPSA and 140 fg/mL for fPSA.

RESULTS

cPSA and fPSA levels were about three times higher in PCOS compared to controls. However, in PCOS, cPSA and fPSA did not differ according to waist-to-hip ratio, Ferriman-Gallwey score, or degree of hyperandrogenemia or oligo-ovulation. In PCOS and control women, serum cPSA and fPSA levels were highly correlated with each other, and with free and total testosterone levels, but not with other hormones. Adjusting for age, body mass index (BMI) and race, cPSA was significantly associated with PCOS, with an odds ratio (OR) of 5.67 (95% confidence interval [CI]: 1.86, 22.0). The OR of PCOS for fPSA was 7.04 (95% CI: 1.65, 40.4). A multivariate model that included age, BMI, race and cPSA yielded an area-under-the-receiver-operating-characteristic curve of 0.89.

CONCLUSIONS

Serum cPSA and fPSA are novel biomarkers for hyperandrogenism in PCOS and may have value for disease diagnosis.

Serum complexed and free prostate specific antigen levels are lower in female elite athletes in comparison to control women

BACKGROUND

We hypothesize that prostate specific antigen (PSA), a protein that it is under regulation by androgens, may be differentially expressed in female elite athletes in comparison to control women.

METHODS

We conducted a cross-sectional study of 106 female athletes and 114 sedentary age-matched controls.  Serum from these women was analyzed for complexed prostate specific antigen (cPSA) and free prostate specific antigen (fPSA), by fifth generation assays with limits of detection of around 6 and 140 fg/mL, respectively.  A panel of estrogens, androgens and progesterone in the same serum was also quantified by tandem mass spectrometry.  Results: Both components of serum PSA (cPSA and fPSA) were lower in the elite athletes vs the control group (P=0.033 and 0.013, respectively).  Furthermore, estrone (p=0.003) and estradiol (p=0.004) were significantly lower, and dehydroepiandrosterone  (p=0.095) and 5-androstene-3β, 17β-diol (p=0.084) tended to be higher in the athletes vs controls. Oral contraceptive use was similar between groups and significantly associated with increased cPSA and fPSA in athletes (p= 0.046 and 0.009, respectively).  PSA fractions were not significantly associated with progesterone changes. The Spearman correlation between cPSA and fPSA in both athletes and controls was 0.75 (P < 0.0001) and 0.64 (P < 0.0001), respectively.  Conclusions: Elite athletes have lower complexed and free PSA, higher levels of androgen precursors and lower levels of estrogen in their serum than sedentary control women.

ABBREVIATIONS

cPSA, complexed PSA; fPSA, free PSA; PCOS, polycystic ovarian syndrome; E1, estrone; E2, estradiol; DHEA, dehydroepiandrosterone, Testo, testosterone; DHT, dihydrotestosterone; PROG, progesterone; Delta 4, androstenedione; Delta 5, androst-5-ene-3β, 17β-diol; BMD, body mineral density; LLOQ, lower limit of quantification; ULOQ, upper limit of quantification; LOD, limit of detection; ACT, α ₁-antichymotrypsin.

Study of Serum Total PSA and Free PSA as an Oncological Marker in Breast Tumour

INTRODUCTION

Breast Cancer (BC) cases are rising alarmingly all over the world and India is not an exception. This rising trend is due to an increased age at first child birth, decreased breast feeding, and the changing lifestyle mostly in urban India. With the advent of more sensitive methodologies and research works in this field, it has been suggested that Prostate Specific Antigen (PSA) plays an important role in the pathogenesis of breast cancer besides other established tumour markers.

AIM

To study the molecular forms of PSA-total and free PSA in benign and malignant tumours and to analyse their association with the tumour burden.

MATERIALS AND METHODS

The present study was conducted in collaboration with Gauhati Medical College and Hospital and Dr B Borooah Cancer Institute, Guwahati, Assam, India. Women in the age group of 18-65 years with recently diagnosed tumour (benign/malignant) in the breast were included in the study. Women taking Oral Contraceptive Pill (OCP), hormone replacement therapy, with past/present history of gynaecological/other malignancy and chronic endocrine disease like diabetes, thyroid disorders were excluded. The case group comprised of 50 female subjects with newly diagnosed Benign Breast Disease (BBD) and 50 subjects with BC, while 50 age matched healthy females without any signs and symptoms of breast discomfort were included in the control group. Laboratory tests done were Serum Total PSA (TPSA), Free PSA (FPSA), Fasting Blood Glucose (FBS), serum urea, serum creatinine and fasting lipid profile. TPSA and FPSA was measured again in both the test groups after 10-14 days of surgery/therapy.

RESULTS

A fall in postoperative value of total and free PSA in BC case group was noticed. In Grade I tumours the mean value of total PSA (1.813 ng/ml) and free PSA (1.149 ng/ml) were higher than those with Grade III tumours (TPSA-1.07 ng/ml and FPSA-1.002 ng/ml). Mean value of Fasting Blood Sugar (FBG), total cholesterol and Low Density Lipoprotein (LDL) in BC case group was higher than the control group.

CONCLUSION

From the study, we can conclude PSA as a possible new marker for diagnosis and prognosis of BC.

Prostate-Specific Antigen as a Marker of Hyperandrogenism in Women and Its Implications for Antidoping

BACKGROUND

Since its discovery in the 1970s, prostate-specific antigen (PSA) has become widely known as a biomarker of prostate cancer in males but has often been overlooked in female malignancies. Although the serum concentration of PSA differs between men and women by about 1000-fold, studies have suggested that PSA concentrations drastically differ among healthy females and those who exhibit increased androgen production.

CONTENT

There have been reports of increased PSA expression in women exhibiting hyperandrogenic states, including polycystic ovary syndrome and hirsutism, as well as marked increases in a subset of breast cancer patients. These findings have not only revealed the remarkable diagnostic potential of PSA in a diverse range of clinical conditions but also point to its potential of becoming a useful biomarker of steroid hormone doping among female athletes. Recently, highly sensitive assays that can measure PSA at low limits of detection have been developed, which will aid in the discrimination of PSA between these different conditions.

SUMMARY

The overall aim of this review is to revisit the expression of PSA in hormonally-regulated tissues and in female malignancies, and to demonstrate how the regulation of PSA permits its use in antidoping initiatives.

Proteomic Analysis of Urine to Identify Breast Cancer Biomarker Candidates Using a Label-Free LC-MS/MS Approach

INTRODUCTION

Breast cancer is a complex heterogeneous disease and is a leading cause of death in women. Early diagnosis and monitoring progression of breast cancer are important for improving prognosis. The aim of this study was to identify protein biomarkers in urine for early screening detection and monitoring invasive breast cancer progression.

METHOD

We performed a comparative proteomic analysis using ion count relative quantification label free LC-MS/MS analysis of urine from breast cancer patients (n = 20) and healthy control women (n = 20).

RESULTS

Unbiased label free LC-MS/MS-based proteomics was used to provide a profile of abundant proteins in the biological system of breast cancer patients. Data analysis revealed 59 urinary proteins that were significantly different in breast cancer patients compared to the normal control subjects (p<0.05, fold change >3). Thirty-six urinary proteins were exclusively found in specific breast cancer stages, with 24 increasing and 12 decreasing in their abundance. Amongst the 59 significant urinary proteins identified, a list of 13 novel up-regulated proteins were revealed that may be used to detect breast cancer. These include stage specific markers associated with pre-invasive breast cancer in the ductal carcinoma in-situ (DCIS) samples (Leucine LRC36, MAST4 and Uncharacterized protein CI131), early invasive breast cancer (DYH8, HBA, PEPA, uncharacterized protein C4orf14 (CD014), filaggrin and MMRN2) and metastatic breast cancer (AGRIN, NEGR1, FIBA and Keratin KIC10). Preliminary validation of 3 potential markers (ECM1, MAST4 and filaggrin) identified was performed in breast cancer cell lines by Western blotting. One potential marker MAST4 was further validated in human breast cancer tissues as well as individual human breast cancer urine samples with immunohistochemistry and Western blotting, respectively.

CONCLUSIONS

Our results indicate that urine is a useful non-invasive source of biomarkers and the profile patterns (biomarkers) identified, have potential for clinical use in the detection of BC. Validation with a larger independent cohort of patients is required in the following study.

Is Serum Prostate-specific Antigen a Diagnostic Marker for Benign and Malignant Breast Tumors in Women?

BACKGROUND

Breast cancer is the most common cancer in women. Prostate-specific antigen (PSA) is a marker of prostate gland malignancy, which has been considered in cases with breast cancer in recent years. The goal of this study was to determine total and free PSA levels in cases with malignant and benign breast lesions.

METHODS

In this case-control study, ninety women with histological proved malignant breast masses and 90 with benign breast masses were enrolled. Total and free PSA levels along with Histological grade and conditions of vascular and perinural invasion, status of hormonal tumor receptors, immune-histo-chemistry markers recorded for all cases. Total and free PSA levels were assessed after treatment in cases with malignant masses.

RESULTS

Total and free PSA levels were significantly higher in cases with malignant masses. The best cut-off point for total PSA to differentiate benign and malignant masses was 0.31 with sensitivity and specificity of 100%, 100% (area under the curve [AUC] =1, P < 0.001) and the best cut-off point for free PSA to differentiate benign and malignant masses was 0.19 with sensitivity and specificity of 100% and 100% (AUC = 1, P < 0.001). After treatment, mean free PSA level was significantly lower than free PSA before treatment (0.23 ± 0.1 vs. 0.3 ± 0.08, P < 0.001).

CONCLUSIONS

Serum PSA level could be applied for differentiating benign and malignant breast masses.

Is there an association between serum prostate-specific antigen values and serum testosterone levels in healthy men?

Purpose

To evaluate the relationship between levels of total testosterone and total prostate-specific antigen (PSA) in healthy men with PSA<4 ng/mL.

Materials and Methods

The study comprised 179 men with a mean age of 59.19±12 years who visited Osmaniye State Hospital, Osmaniye, Turkey, between January 2006 and January 2007 for a routine checkup. The patients were divided into two subgroups: patients with PSA<2.5 mg/ml (group I, n=160 patients) and patients with PSA of 2.5 to 4 ng/mL (group II, n=19 patients). The relationship between PSA and testosterone levels was investigated in both groups and in patients aged <60 years. The mean testosterone level was calculated for patients aged <50 years and was compared with the mean value of patients aged ≥50 years.

Results

In all patients, the mean values for serum PSA and total testosterone were 1.27±0.88 ng/mL and 404.04±158.86 ng/mL, respectively. No correlation was detected between serum PSA and testosterone levels in either subgroup (group I, r=0.072, p=0.363; group II, r=0.031, p=0.900) or in patients aged <60 years (r=0.032, p=0.72). The mean values of testosterone in patients aged ≥50 years and in patients aged <50 years were 417.01±163.35 and 344.16±120.21 ng/dL, respectively (p=0.02).

Conclusions

No impact of testosterone was found on the PSA level in healthy men with PSA <4 ng/mL. Therefore, a high serum testosterone level may not mandate adjustment of PSA values. This serum sex hormone showed a significant increment after the age of 50 years. Further studies including a larger number of patients should be carried out to confirm these findings.

microRNA-18b is upregulated in breast cancer and modulates genes involved in cell migration

microRNAs are small non-coding RNAs of ~22 nucleotides that function at post-transcriptional level as negative regulators of gene expression. Aberrant expression of microRNAs could promote uncontrolled proliferation, migration and invasion of human cancer cells. In this study, we analyzed the expression of microRNA-18b (miR-18b) in breast cancer cell lines and in a set of clinical specimens. Our results showed that miR-18b was upregulated in four out of five breast cancer cell lines and also in breast tumors. In order to identify potential gene targets, we carried out transcriptional profiling of MDA-MB-231 breast cancer cells that ectopically expressed miR-18b. Our results showed that 263 genes were significantly modulated in miR-18b-deficient cells (fold change >1.5; P≤0.05). We found that knock-down of miR-18b induced the upregulation of 55 olfactory receptor (OR) genes and nine genes (NLRP7, KLK3, OLFM3, POSTN, MAGED4B, KIR3DL3, CRX, SEMG1 and CEACAM5) with key roles in cell migration and metastasis. Consistently, we found that ectopic inhibition of miR-18b suppressed the migration of two breast cancer cell models in vitro. In conclusion, we have uncovered genes directly or indirectly modulated by miR-18b which may represent potential therapeutic targets in breast cancer. Our data also pointed out a role of miR-18b in migration of breast cancer cells.

The investigation of total PSA, free PSA, and free/total PSA ratio in patients with liver cirrhosis patients according to Child-Pugh score

OBJECTIVE

To investigate the total prostate-specific antigen (tPSA), free PSA (fPSA), and free/total PSA (fPSA/tPSA) ratio in patients with liver cirrhosis (LC) according to the severity of hepatic insufficiency.

METHODS

Eighty-two male patients with LC were studied. The severity of liver disease was categorized by Child-Pugh score (Child-Pugh A, B, and C). Forty-two age-matched healthy subjects were used as a control group. The tPSA, fPSA, fPSA/tPSA ratio, total prostate volume (TPV), total testosterone (TT), and total protein (TP) were measured. The LC group was compared with the control group in terms of these parameters. In addition, intra-comparison and inter-comparison was made between all the Child-Pugh groups and normal subjects, in terms of these parameters.

RESULTS

The tPSA and fPSA levels in LC cases, Child-Pugh A, Child-Pugh B, and Child-Pugh C groups were significantly decreased compared with the control group. The ratio of fPSA/tPSA in the LC subjects and Child-Pugh A groups significantly increased compared with the control group. TT, TP levels, and TPV in patients with LC were significantly lower compared with the control group and the results were significantly correlated with the Child-Pugh score.

CONCLUSION

The present study reveals that tPSA and fPSA were decreased in patients with LC in comparison to healthy subjects in terms of 3 mechanisms. First, it might be due to shrunken prostatic volume. Second, it also resulted in decreased levels of testosterone because of the abnormality of hypothalamic-pituitary-testicular axis. Third, it might be the diminished serum protein level in the composition of the PSA.

Prostate-specific antigen and hormone receptor expression in male and female breast carcinoma

Background

Prostate carcinoma is among the most common solid tumors to secondarily involve the male breast. Prostate specific antigen (PSA) and prostate-specific acid phosphatase (PSAP) are expressed in benign and malignant prostatic tissue, and immunohistochemical staining for these markers is often used to confirm the prostatic origin of metastatic carcinoma. PSA expression has been reported in male and female breast carcinoma and in gynecomastia, raising concerns about the utility of PSA for differentiating prostate carcinoma metastasis to the male breast from primary breast carcinoma. This study examined the frequency of PSA, PSAP, and hormone receptor expression in male breast carcinoma (MBC), female breast carcinoma (FBC), and gynecomastia.

Methods

Immunohistochemical staining for PSA, PSAP, AR, ER, and PR was performed on tissue microarrays representing six cases of gynecomastia, thirty MBC, and fifty-six FBC.

Results

PSA was positive in two of fifty-six FBC (3.7%), focally positive in one of thirty MBC (3.3%), and negative in the five examined cases of gynecomastia. PSAP expression was absent in MBC, FBC, and gynecomastia. Hormone receptor expression was similar in males and females (AR 74.1% in MBC vs. 67.9% in FBC, p = 0.62; ER 85.2% vs. 68.5%, p = 0.18; and PR 51.9% vs. 48.2%, p = 0.82).

Conclusions

PSA and PSAP are useful markers to distinguish primary breast carcinoma from prostate carcinoma metastatic to the male breast. Although PSA expression appeared to correlate with hormone receptor expression, the incidence of PSA expression in our population was too low to draw significant conclusions about an association between PSA expression and hormone receptor status in breast lesions.

Kallikrein-related peptidase genes as promising biomarkers for prognosis and monitoring of human malignancies

Tissue kallikrein (KLK1) and the kallikrein-related peptidase (KLK2-15) genes encode for a subgroup of 15 homologous secreted serine proteases possessing numerous physiological roles, such as the regulation of blood pressure, hormone processing and tissue remodeling. The expression of KLKs is detected in a broad spectrum of human tissues where it has been found to be regulated mainly by steroids hormones. The aberrant expression of KLKs, presented in many human malignancies, highlights the significance of this gene family for early diagnosis, prognosis and monitoring of cancer patients, as it is strongly emphasized by the routine use of PSA (KLK3) for prostate cancer management. Here, we review the presently known data regarding the role of KLKs as cancer biomarkers, giving emphasis on novel information about the subject.

Kallikreins on steroids: structure, function, and hormonal regulation of prostate-specific antigen and the extended kallikrein locus

The 15 members of the kallikrein-related serine peptidase (KLK) family have diverse tissue-specific expression profiles and putative proteolytic functions. The kallikrein family is also emerging as a rich source of disease biomarkers with KLK3, commonly known as prostate-specific antigen, being the current serum biomarker for prostate cancer. The kallikrein locus is also notable because it is extraordinarily responsive to steroids and other hormones. Indeed, at least 14 functional hormone response elements have been identified in the kallikrein locus. A more comprehensive understanding of the transcriptional regulation of kallikreins may help the field make more informed hypotheses about the physiological functions of kallikreins and their effectiveness as biomarkers. In this review, we describe the organization of the kallikrein locus and the structure of kallikrein genes and proteins. We also focus on the transcriptional regulation of kallikreins by androgens, progestins, glucocorticoids, mineralocorticoids, estrogens, and other hormones in animal models and human prostate, breast, and reproductive tract tissues. The interaction of the androgen receptor with androgen response elements in the promoter and enhancer of KLK2 and KLK3 is also summarized in detail. There is evidence that all kallikreins are regulated by multiple nuclear receptors. Yet, apart from KLK2 and KLK3, it is not clear whether all kallikreins are direct transcriptional targets. Therefore, we argue that gaining more detailed information about the mechanisms that regulate kallikrein expression should be a priority of future studies and that the kallikrein locus will continue to be an important model in the era of genome-wide analyses.

Detection of circulating tumor cells in prostate cancer patients: methodological pitfalls and clinical relevance

Disseminated malignancy is the major cause of prostate cancer-related mortality. Circulating tumor cells (CTCs) are essential for the establishment of metastasis. Various contemporary and molecular methods using prostate-specific biomarkers have been applied to detect extraprostatic disease that is undetectable by conventional imaging techniques, assessing the risk for disease recurrence after therapy of curative intent. However, the clinical relevance of CTC detection is still controversial. We review current literature regarding molecular methods used for the detection of CTCs in the peripheral blood and bone marrow biopsies of patients with prostate cancer, and we discuss the methodological pitfalls that influence the clinical significance of molecular staging.

The Tissue Kallikrein Family of Serine Proteases: Functional Roles in Human Disease and Potential as Clinical Biomarkers

Prostate specific antigen (PSA) or human kallikrein 3 (hK3) has long been an effective biomarker for prostate cancer. Now, other members of the tissue kallikrein (KLK) gene family are fast becoming of clinical interest due to their potential as prognostic biomarkers. particularly for hormone dependent cancers. The tissue kallikreins are serine proteases that are encoded by highly conserved multi-gene family clusters in rodents and humans. The rat and mouse loci contain 10 and 25 functional genes, respectively, while the human locus at 19q 13.4 contains 15 genes. The structural organization and size of these genes are similar across species; all genes have 5 coding exons that encode a prepro-enzyme. Although the physiological activators of these zymogens have not been described, in vitro biochemical studies show that some kallikreins can auto-activate and others can activate each other, suggesting that the kallikreins may participate in an enzymatic cascade similar to that of the coagulation cascade. These genes are expressed, to varying degrees, in a wide range of tissues suggesting a functional involvement in a diverse range of physiological and pathophysiological processes. These include roles in normal skin desquamation and psoriatic lesions, tooth development, neural plasticity, and Alzheimer's disease (AD). Of particular interest is the expression of many kallikreins in prostate, ovarian, and breast cancers where they are emerging as useful prognostic indicators of disease progression.

Cellular distribution of human tissue kallikreins: immunohistochemical localization

We have studied the immunohistochemical expression (IE) of eight non-tissue-specific human kallikreins (hKs) (hK5, 6, 7, 10, 11, 12, 13, and 14) in different normal tissues. The IE was always cytoplasmic, showing a characteristic pattern in some tissues. Comparison of the IE of all hKs studied in the different tissues revealed no major differences, suggesting that they share a common mode of regulation. Furthermore, hKs were immunohistochemically revealed in a variety of tissues, indicating that no protein is tissue-specific (except for hK2 and hK3, which have tissue-restricted expression). In general, our results correspond well with data from RT-PCR and ELISA assays. Glandular epithelia constitute the main kallikrein IE sites, and the staining in their secretions confirms that these proteases are secreted. A variety of other tissues express the proteins as well. We have also immunohistochemically evaluated all the above hKs in several malignant tissues. Tumors arising from tissues expressing kallikreins tested positive. Corresponding to the IE in normal glandular tissues, most hKs were expressed in adenocarcinomas. The prognostic value of several hKs was studied in series of prostate, renal cell, colon and urothelial carcinomas.

Effect of Testosterone Administration on Serum and Urine Kallikrein Concentrations in Female-to-Male Transsexuals

Background: Concentrations of human tissue kallikreins (hKs), a group of 15 secreted serine proteases found in many tissues, are modulated by steroid hormones in cancer cell lines. To gain insight into in vivo kallikrein regulation we measured kallikrein concentrations in serum and urinary tissue in female-to-male transsexuals before and after testosterone administration.

Methods: We collected blood and urine samples before treatment and after 4 and 12 months from 28 female-to-male transsexuals who received 250 mg of testosterone esters intramuscularly every 2 weeks. We used ELISA assays to measure multiple kallikreins in serum and urine.

Results: After testosterone administration, serum testosterone concentrations increased by ∼15-fold. Serum kallikrein concentrations increased dramatically for hK3 (prostate-specific antigen) and increased moderately for hK2, hK5, hK6, hK7, hK8, hK10, and hK11. In urine, we noted major increases for hK3 and hK2 only. For all other kallikrein concentrations, we observed no considerable changes.

Conclusions: We conclude that, in serum and urine of female-to-male transsexuals after testosterone administration, hK3 (prostate-specific antigen) and to a lesser extent hK2 concentrations increase dramatically, but concentration of other kallikreins increase either moderately in serum (hK5, hK6, hK7, hK8, hK10, and hK11) or not at all in either serum (hK4, hK13, hK14) or urine (hK4, hK5, hK6, hK7, hK8, hK10, hK11, hK13, hK14).

Effects of Long-term Androgen Administration on Breast Tissue of Female-to-Male Transsexuals

Our aim was to examine the effects of androgen administration on breast tissue histology of female-to-male transsexuals and to study the immunohistochemical expression of three human tissue kallikreins, hK3 (PSA), hK6, and hK10. We studied 23 female-to-male transsexuals who were treated with injectable testosterone for 18-24 months. We also used 10 control female breast tissues. All tissues were fixed in buffered formalin, embedded in paraffin, and examined by hematoxylin-eosin staining and immunohistochemical staining for PSA, hK6, and hK10. Females treated with androgens exhibited similar involutionary changes as those seen in breast of menopausal women, such as marked reduction of glandular tissue, involution of the lobuloalveolar structures, and prominence of fibrous connective tissue, but presence of only small amounts of fat tissue. Fibrocystic lesions were generally not observed. In immunohistochemistry, in control breast tissues, we found moderate to strong cytoplasmic immunoexpression of hK6 and hK10 in the epithelial ductal and lobuloalveolar structures, but myoepithelial cells were negative. Luminal secretions were also positive. In menopausal breast, the immunoexpression of hK6 and hK10 was weaker and focal. No control case showed immunoexpression for PSA. In female-to-male transsexuals, one case showed focal PSA cytoplasmic immunoexpression in the epithelium of moderately involuting lobules. Long-term administration of androgens in female-to-male transsexuals causes marked reduction of glandular tissue and prominence of fibrous connective tissue. These changes are similar to those observed at the end-stage of menopausal mammary involution. (J Histochem Cytochem 54:905-910, 2006)

Evaluation of precursor prostate-specific antigen isoform ratios in the detection of prostate cancer

OBJECTIVE

Disease-associated isoforms of the prostate-specific antigen (PSA) have recently been identified. We evaluated the efficacy of using precursor isoforms of PSA (pPSA) and their ratios for the detection of prostate cancer.

METHODS

Serum concentrations of [-2], [-4], and [-7]pPSA, BPSA, and free PSA (fPSA) were retrospectively measured in 43 selected men. Of the 43 men, 15 had clinical T2 prostate cancer with ultrasound-estimated prostate volumes (PVs) of >50 cm(3), 13 had clinical T2 prostate cancer with (PVs) <25 cm(3), and 15 were prostate cancer-free with PV >50 cm(3). We calculated sum pPSA ([-2]+[-4]+[-7]pPSA). We also compared the ratios of: free/total PSA, [-2]pPSA/fPSA, [-2]pPSA/BPSA, [-2]pPSA/(fPSA-BPSA), [-2]pPSA/(fPSA-sum pPSA), and [-2]pPSA/{fPSA-(sum pPSA+BPSA)} among these three groups.

RESULTS

The median [-2]pPSA/(fPSA-sum pPSA) ratio was significantly higher in men with prostate cancer with or without large PV compared with men with large PV without prostate cancer. Values for median [-2]pPSA/free PSA ratio were higher in men with prostate cancer with or without large PV compared with men with large PV, and without prostate cancer, but the differences were not statistically significant.

CONCLUSIONS

In this preliminary study, [-2]pPSA/(fPSA-sum pPSA) ratio was not associated with prostate gland volume but was associated with prostate cancer. This ratio may be useful in the detection of prostate cancer, particularly in men with larger glands.

Human tissue kallikrein gene family: applications in cancer

Human tissue kallikrein genes, located on the long arm of chromosome 19, are a subgroup of the serine protease family of proteolytic enzymes. Initially thought to consist of three members, the human kallikrein locus has now been extended and includes 15 tandemly located genes. These genes, and their protein products, share a high degree of homology and are expressed in a wide array of tissues, mainly those that are under steroid hormone control. PSA (hK3) is one of the human kallikreins, and is the most useful tumor marker for prostate cancer screening, diagnosis, prognosis and monitoring. hK2, another prostate-specific kallikrein, has also been proposed as a complementary prostate cancer biomarker. In the past 5 years, the newly discovered kallikreins (KLK4-KLK15) have been associated with several types of cancer. For example, hK4, hK5, hK6, hK7, hK8, hK10, hK11, hK13 and hK14 are emerging biomarkers for ovarian, breast, prostate and testicular cancer. New evidence raises the possibility that some kallikreins are directly involved with cancer progression. We here review the evidence linking kallikreins and cancer and their applicability as novel biomarkers for cancer diagnosis and management.

Expression of prostate-specific antigen (PSA) and human glandular kallikrein 2 (hK2) in ileum and other extraprostatic tissues

Prostate-specific antigen (PSA) is a widely used marker for prostate cancer. In the literature, there are reports of nonprostatic expression of PSA that potentially can affect early diagnosis. However, the results are scattered and inconclusive, which motivated us to conduct a more comprehensive study of the tissue distribution of PSA and the closely related protein human glandular kallikrein 2 (hK2). RT-PCR, in situ hybridization and immunohistochemistry were used to detect expression of both PSA and hK2 in secretory epithelial cells of trachea, thyroid gland, mammary gland, salivary gland, jejunum, ileum, epididymis, seminal vesicle and urethra, as well as in Leydig cells, pancreatic exocrine glands and epidermis. Immunometric measurements revealed that the concentration of PSA in nonprostatic tissues represents less than 1% of the amount in normal prostate. Pronounced expression of PSA was detected in the Paneth cells in ileum, which prompted us to compare functional parameters of PSA in ileum and prostate. We found that in homogenates from these 2 tissues, PSA manifested equivalent amidolytic activity and capacity to form complexes with protease inhibitors in blood in vitro. Thus, PSA released from sources other than the prostate may add to the plasma pool of this protein, but given the lower levels detected from those sites, it is unlikely that nonprostatic PSA normally can interfere with the diagnosis of prostate cancer. Nevertheless, this risk should not be neglected as it may be of clinical significance under certain circumstances. Supplementary material for this article can be found on the International Journal of Cancer website at http://www.interscience.wiley.com/jpages/0020-7136/suppmat/index.html.

Human Tissue Kallikreins: Physiologic Roles and Applications in Cancer

Tissue kallikreins are members of the S1 family (clan SA) of trypsin-like serine proteases and are present in at least six mammalian orders. In humans, tissue kallikreins (hK) are encoded by 15 structurally similar, steroid hormone–regulated genes (KLK) that colocalize to chromosome 19q13.4, representing the largest cluster of contiguous protease genes in the entire genome. hKs are widely expressed in diverse tissues and implicated in a range of normal physiologic functions from the regulation of blood pressure and electrolyte balance to tissue remodeling, prohormone processing, neural plasticity, and skin desquamation. Several lines of evidence suggest that hKs may be involved in cascade reactions and that cross-talk may exist with proteases of other catalytic classes. The proteolytic activity of hKs is regulated in several ways including zymogen activation, endogenous inhibitors, such as serpins, and via internal (auto)cleavage leading to inactivation. Dysregulated hK expression is associated with multiple diseases, primarily cancer. As a consequence, many kallikreins, in addition to hK3/PSA, have been identified as promising diagnostic and/or prognostic biomarkers for several cancer types, including ovarian, breast, and prostate. Recent data also suggest that hKs may be causally involved in carcinogenesis, particularly in tumor metastasis and invasion, and, thus, may represent attractive drug targets to consider for therapeutic intervention.

Volume-based evaluation of serum assays for new prostate-specific antigen isoforms in the detection of prostate cancer

OBJECTIVES

Recently, disease-specific isoforms of the prostate-specific antigen (PSA) have been identified. We evaluated the efficacy of precursor isoforms of PSA (pPSA) and an internally cleaved form of PSA referred to as the benign prostatic hyperplasia-associated PSA (BPSA) for the detection of prostate cancer.

METHODS

Serum concentrations of [-2], [-4], and [-7]pPSA, sum pPSA ([-2] + [-4] + [-7]pPSA), and BPSA were retrospectively measured in 43 selected men. The median total PSA levels in men with and without cancer were 6.5 microg/L (range 0.4 to 12.1 microg/L) and 6.1 microg/L (range 3.7 to 21.5 microg/L), respectively. Of the 43 men, 15 had clinical T2 prostate cancer with an ultrasound-estimated prostate volume (PV) of greater than 50 mL, 13 had clinical T2 prostate cancer with PV less than 25 mL, and 15 were prostate cancer free with PV greater than 50 mL.

RESULTS

The median values for BPSA, free-to-total PSA ratio (f/tPSA), and benign-to-total PSA ratio (B/tPSA) differed statistically between men with cancer and a PV less than 25 mL and men with cancer and a PV greater than 50 mL (P <0.05) and between the men with cancer and a PV less than 25 mL and men without cancer and a PV greater than 50 mL (P <0.005). All evaluated variables had no correlation with tumor volume in 15 men who had undergone radical prostatectomy.

CONCLUSIONS

In this preliminary study, the level of [-2], [-4], sum pPSA, and BPSA seemed to be PV related, but only BPSA and B/tPSA and f/tPSA were significantly associated with PV. Therefore, pPSA did not aid in better discriminating cancer from noncancer.

Kallikrein gene downregulation in breast cancer

Recent evidence suggests that many members of the human kallikrein gene family are differentially regulated in breast cancer and other endocrine-related malignancies. In this study, we utilised the serial analysis of gene expression (SAGE) and expressed sequence tag (EST) databases of the Cancer Genome Anatomy Project (CGAP) to perform in silico analyses of the expression pattern of the 15 human kallikrein genes in normal and cancerous breast tissues and cell lines using different analytical tools such as Virtual Northern blotting, Digital Differential Display and X-profiler. Our results indicate that at least four kallikrein genes (KLK5, 6, 8, 10) are downregulated in breast cancer. Probing eight normal and 24 breast cancer SAGE libraries with gene-specific tags for each of the above kallikreins indicated moderate-to-high expression densities in normal breast (27–319 tags per million; tpm, in two to five out of eight libraries), compared to no or low expression (0 – 34 tpm in zero to two libraries out of 24) in breast cancer. These data were verified by screening the EST databases, where all mRNA clones isolated for these genes, except for one in each, were from normal breast libraries, with no clones detected from breast cancer tissues or cell lines (with the exception of KLK8). X-profiler comparison of two pools of normal and breast cancer libraries further verified the presence of significant downregulation of expression levels of 4 of the kallikreins genes (KLK5, 6, 10, 12). We experimentally verified the downregulation of these four kallikreins (KLK5, 6, 8, 10 and 12) by RT – PCR analysis.

The effect of seminal vesicle-sparing radical prostatectomy on serum prostate-specific antigen level

OBJECTIVE

To investigate if the remaining seminal vesicle tips can affect serum levels of prostate-specific antigen (PSA) in patients after seminal vesicle-sparing radical prostatectomy (SVRP).

PATIENTS AND METHODS

Thirty-six patients were treated by either radical retropubic prostatovesiculectomy (23) or SVRP (13). Serum PSA was monitored in all patients before surgery, and at 6 weeks and 30 months afterward. Samples of normal seminal vesicles from radical cystectomies (six) were also snap-frozen and either processed for semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) using primers against PSA and alpha-actin (for normalization) or for PSA immunohistochemistry.

RESULTS

RT-PCR and sequencing showed that the seminal vesicles synthesise PSA mRNA. Furthermore, PSA peptide was detectable in the glandular epithelium of the seminal vesicle using immunohistochemical methods. There was no significant difference in serum PSA levels after standard or SVRP, with median (range) values (ng/mL) at 6 weeks of 0.04 (0.04-0.9) and 0.04 (0.04-0.66) and at 30 months of 0.17 (0.04-3.8) and 0.22 (0.04-58.2), respectively.

CONCLUSION

Although the seminal vesicles produce PSA, the PSA derived from the remaining seminal vesicle tips after SVRP has no effect on the oncological follow-up of these patients.

Expression of androgen receptor and prostate-specific antigen in male breast carcinoma

BACKGROUND

The androgen-regulated proteins prostate-specific antigen (PSA) and prostate-specific acid phosphatase (PSAP) are present in high concentrations in normal prostate and prostatic cancer and are considered to be tissue-specific to prostate. These markers are commonly used to diagnose metastatic prostate carcinoma at various sites including the male breast. However, expression of these two proteins in tumors arising in tissues regulated by androgens such as male breast carcinoma has not been thoroughly evaluated.

METHODS

In this study we analyzed the expression of PSA, PSAP and androgen receptor (AR) by immunohistochemistry in 26 cases of male breast carcinomas and correlated these with the expression of other prognostic markers.

RESULTS

AR, PSA and PSAP expression was observed in 81%, 23% and 0% of carcinomas, respectively. Combined expression of AR and PSA was observed in only four tumors.

CONCLUSION

Although the biological significance of PSA expression in male breast carcinomas is not clear, caution should be exercised when it is used as a diagnostic marker of metastatic prostate carcinoma.

Recombinant prostate specific antigen inhibits angiogenesis in vitro and in vivo

BACKGROUND

Prostate specific antigen (PSA) is a kallikrein family member with serine protease activity commonly used as a diagnostic marker for prostate cancer. We recently described anti-angiogenic properties of PSA [Fortier et al.: JNCI 91:1635-1640].

METHODS

Two forms of PSA were cloned and expressed in Pichia pastoris: one, an intact PSA with an N-terminus of IVGGVS em leader; the second, an N-1 PSA variant. The recombinant proteins were tested for serine protease activity and for anti-angiogenic activity in vitro and in vivo.

RESULTS

The rate of substrate hydrolysis by the intact recombinant PSA was similar to that of PSA isolated and purified from human seminal plasma. In contrast, the N-1 PSA variant lacked serine protease activity. In an endothelial cell migration assay, the concentration that resulted in 50% inhibition (IC(50)) was: 0.5 microM for native PSA, 0.5 microM for intact recombinant protein, and 0.1 microM for the N-1 variant PSA. Both the intact recombinant and the N-1 recombinant PSA inhibited angiogenesis in vivo.

CONCLUSIONS

Purified recombinant PSA inhibits angiogenesis, proving the concept that PSA is an anti-angiogenic, and serine protease activity, as determined by synthetic substrate hydrolysis, is distinct from the anti-angiogenic properties of PSA.

Human kallikrein 13 expression in normal tissues: an immunohistochemical study

The human tissue kallikrein 13 gene (KLK13), encoding for hK13 protein, was recently cloned and characterized. Here we describe the immunohistochemical (IHC) localization of hK13 in normal human tissues and compare it with the expression of two other kallikreins, hK6 and hK10. We performed the streptavidin-biotin IHC method on 204 paraffin blocks from archival, current, and autopsy material prepared from almost every normal human tissue, using a polyclonal and a monoclonal hK13 antibody. The staining was cytoplasmic and both antibodies yielded similar results. The hK13 protein was revealed in a variety of tissues, mainly in glandular epithelia. Other epithelia that expressed hK13 included the urothelium, the spermatic epithelium, and the epithelium of the choroid plexus. hK13 was intensely immunoexpressed by some endocrine organs, such as the adenohypophysis, the thyroid gland, the parathyroid glands, the adrenal medulla, the Leydig cells of the testis, and the cells of the endocrine pancreas. Immunoreactivity was also observed in the primordial follicles, the corpus luteum, and sparse luteinized cells in the stroma of the ovary, the trophoblastic cells of the placenta, the Hassall's corpuscles of the thymus, and chondrocytes. Nerves and ganglia of the peripheral nervous system, and both neurons and glial cells in the central nervous system, were positive. In short, hK13 was expressed by many glandular epithelia, some endocrine organs, and some specialized epithelia and cells. Comparison of these data with hK6 and hK10 expression suggests that the three kallikreins have a similar IHC pattern in normal human tissues.

Angiopoietin-2 expression in breast cancer correlates with lymph node invasion and short survival

Angiogenic factors produced by tumor cells are essential for tumor growth and metastasis. In our study, the expression of Angiopoietin-1 (ANG1) and Angiopoietin-2 (ANG2) mRNA in archival human breast cancer tumor samples and in 6 breast cancer cell lines was investigated. Total RNA from biopsies of 38 breast cancer patients was extracted and ANG1 and ANG2 mRNA expression was measured by means of quantitative real-time RT-PCR (Taqman). Matching data with available clinicopathologic and biochemical data revealed a significant association between ANG2 expression and axillary lymph node invasion. Univariate and multivariate survival analysis, by means of Kaplan-Meier method and Cox's proportional hazards model, showed significant and independent association between ANG2 mRNA level and both disease-free (p < 0.0001) and overall survival (p < 0.0003). An important fact is that, notwithstanding the small number of cases examined, this association was confirmed also in the group of lymph node-negative patients (DFS, p < 0.003; OS, p < 0.020). Immunohistochemical analysis demonstrated that Ang2 is expressed by both tumor cells and endothelial elements. Expression in tumor cells was confirmed by studying a panel of human breast carcinoma cell lines in culture by RT-PCR. In ZR75.1 and T47D cells, expression of ANG2 mRNA was increased up to 10-fold by treatment with estrogen within 24 hr. Although preliminary, these data suggest a possible role of ANG2 as a prognostic factor for primary breast cancer.

Influence of age, anthropometry, and hepatic and renal function on serum prostate-specific antigen levels in healthy middle-age men

OBJECTIVES

To test the hypothesis of a causal relationship between clinical parameters, including age, anthropometry, and hepatic or renal function tests and serum prostate-specific antigen (PSA) levels and to determine the predictors of high serum PSA concentrations in healthy middle-age men.

METHODS

Between January 1999 and December 2000, 6005 healthy men 40 to 59 years old who visited our hospital for a routine health checkup were entered into the study. The association between the clinical parameters and a high serum PSA level (greater than 2.5, 3.0, 3.5, or 4.0 ng/mL) was studied in three groups: the 10% with low clinical parameters, the 10% with high clinical parameters, and the remainder as a reference group.

RESULTS

The univariate logistic regression analysis indicated that high or low age, body weight, body mass index, creatinine, and creatinine clearance were significant factors in relation to serum PSA concentration compared with the reference group. In the multivariate model used, only older age was positively related to the serum PSA concentration.

CONCLUSIONS

The results of anthropometry and hepatic and renal function tests do not influence the serum PSA level in this population. Our findings suggest that serum PSA may be a reliable marker in middle-age men without severe hepatic or renal disease.

The androgen-regulated gene human kallikrein 15 (KLK15) is an independent and favourable prognostic marker for breast cancer

Many kallikrein genes were found to be differentially expressed in various malignancies, and prostate specific antigen (encoded by the KLK3 gene) is the best tumour marker for prostate cancer. Prostate specific antigen has recently been shown to be an independent favourable prognostic marker for breast cancer. KLK15 is newly discovered kallikrein gene that is located adjacent to KLK3 on chromosome 19q13.4. KLK15 has 41% similarity to KLK3 and the encoded protein, hK15, can activate pro-prostate specific antigen. We studied the expression of KLK15 by real-time quantitative reverse transcriptase-polymerase chain reaction in 202 tissues from patients with breast carcinoma of various stages, grades and histological types. KLK15 expression was found to be a significant predictor of progression-free survival (hazard ratio of 0.41 and P=0.011) and overall survival (hazard ratio of 0.34 and P=0.009). When all other known confounders were controlled in the multivariate analysis, KLK15 retained its prognostic significance. Higher concentrations of KLK15 mRNA were found more frequently in node negative patients (P=0.042). No association was found between KLK15 expression and any other clinicopathological variable. Further, KLK15 is an independent prognostic factor of progression-free survival and overall survival in the subgroup of patients with lower grade and those with oestrogen receptor and progesterone receptor negative tumours in both univariate and multivariate analysis. KLK15 levels of expression were slightly higher (although not statistically significant) in the oestrogen receptor negative and progesterone receptor negative subgroups of patients. KLK15 is up-regulated by androgens in breast cancer cell lines. Time-course and blocking experiments suggest that this regulation is mediated through the androgen receptor.

Human kallikrein 10 expression in normal tissues by immunohistochemistry

The normal epithelial cell-specific 1 (NES1) gene (official name kallikrein gene 10, KLK10) was recently cloned and encodes for a putative secreted serine protease (human kallikrein 10, hK10). Several studies have confirmed that hK10 shares many similarities with the other kallikrein members at the DNA, mRNA, and protein levels. The enzyme was found in biological fluids, tissue extracts, and serum. Here we report the first detailed immunohistochemical (IHC) localization of hK10 in normal human tissues. We used the streptavidin-biotin method with two hK10-specific antibodies, a polyclonal rabbit and a monoclonal mouse antibody, developed in house. We analyzed 184 paraffin blocks from archival, current, and autopsy material, prepared from almost every normal human tissue. The staining pattern, the distribution of the immunostaining, and its intensity were studied in detail. Previously, we reported the expression of another novel human kallikrein, hK6, by using similar techniques. The IHC expression of hK10 was generally cytoplasmic and not organ-specific. A variety of normal human tissues expressed the protein. Glandular epithelia constituted the main immunoexpression sites, with representative organs being the breast, prostate, kidney, epididymis, endometrium, fallopian tubes, gastrointestinal tract, bronchus, salivary glands, bile ducts, and gallbladder. The choroid plexus epithelium, the peripheral nerves, and some neuroendocrine organs (including the islets of Langerhans, cells of the adenohypophysis, the adrenal medulla, and Leydig cells) expressed the protein strongly and diffusely. The spermatic epithelium of the testis expressed the protein moderately. A characteristic immunostaining was observed in Hassall's corpuscles of the thymus, oxyphilic cells of the thyroid and parathyroid glands, and chondrocytes. Comparing these results with those of hK6, we observed that both kallikreins had a similar IHC expression pattern.

Human Tissue Kallikreins: A Family of New Cancer Biomarkers

Kallikreins are a subgroup of the serine protease enzyme family. Until recently, it was thought that the human kallikrein gene family contained only three members. In the past 3 years, the entire human kallikrein gene locus was discovered and found to contain 15 kallikrein genes. Kallikreins are expressed in many tissues, including steroid hormone-producing or hormone-dependent tissues such as the prostate, breast, ovary, and testis. Most, if not all, kallikreins are regulated by steroid hormones in cancer cell lines. There is strong but circumstantial evidence linking kallikreins and cancer. Prostate-specific antigen (PSA; hK3) and, more recently, human glandular kallikrein (hK2) are widely used tumor markers for prostate cancer. Three other kallikreins, hK6, hK10, and hK11, are emerging new serum biomarkers for ovarian and prostate cancer diagnosis and prognosis. Several other kallikreins are differentially expressed at both the mRNA and protein levels in various endocrine-related malignancies, and they have prognostic value. The coexpression of many kallikreins in the same tissues (healthy and malignant) points to the possible involvement of kallikreins in cascade enzymatic pathways. In addition to their diagnostic/prognostic potential, kallikreins may also emerge as attractive targets for therapeutics.

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.

Design of new and sensitive fluorogenic substrates for human kallikrein hK3 (prostate-specific antigen) derived from semenogelin sequences

Human kallikrein hK3 (prostate-specific antigen) is a chymotrypsin-like serine protease which is widely used in the diagnosis of prostate cancer. Assays of the enzymatic activity of hK3 in extracellular fluids have been limited by a lack of sensitive synthetic substrates. This report describes the design of a series of internally quenched fluorescent peptides containing an amino acid sequence based on preferential hK3 cleavage sites in semenogelins. Those were identified by 2-D gel electrophoresis analysis and N-terminal sequencing of semenogelin fragments generated by ex vivo proteolysis in freshly ejaculated semen. These peptides were cleaved by hK3 at the C-terminal of certain tyrosyl or glutaminyl residues with k(cat)/K(m) values of 15000-60000 M(-1) s(-1). The substrate Abz-SSIYSQTEEQ-EDDnp was cleaved at the Tyr-Ser bond with a specificity constant k(cat)/K(m) of 60000 M(-1) s(-1), making it the best substrate for hK3 described to date.

The spectrum of human kallikrein 6 (zyme/protease M/neurosin) expression in human tissues as assessed by immunohistochemistry

The KLK6 gene is a new member of the human kallikrein gene family and encodes for a secreted protease, human kallikrein 6 (hK6; also known as zyme/protease M/neurosin). No study has as yet reported detailed immunohistochemical localization of hK6 in human tissues. Our purpose was to examine the expression of hK6 in human tissues by immunohistochemistry. We have analyzed 199 paraffin blocks from archival, current, and autopsy material prepared from almost every normal human tissue. We employed an hK6-specific polyclonal rabbit antibody and avidin-biotin to localize hK6 by IHC. The staining pattern, the distribution of the immunostaining, and its intensity were studied in detail. The IHC expression of zyme was generally cytoplasmic. Various normal human tissues expressed the protein abundantly. Glandular epithelia constituted the main immunoexpression sites, with representative organs being the breast, prostate, kidney, endometrium, colon, appendix, salivary glands, bile ducts, and gallbladder. The small intestine, stomach, endocervix, Fallopian tube, epididymis, bronchus, and upper respiratory tract showed a focal expression as well. Choroid plexus epithelium, peripheral nerves, and some neuroendocrine cells (including the islets of Langerhans, cells in the anterior pituitary gland, and adrenal medulla) expressed the protein strongly and diffusely. A characteristic immunostaining was observed in the Hassall's corpuscles of the thymus, the oxyphilic cells of the thyroid and parathyroid glands, the primordial follicles of the ovary, dendritic cells mainly in the spleen, and in various cells of the placenta.