Supervised machine learning enables non-invasive lesion characterization in primary prostate cancer with [68Ga]Ga-PSMA-11 PET/MRI

PURPOSE

Risk classification of primary prostate cancer in clinical routine is mainly based on prostate-specific antigen (PSA) levels, Gleason scores from biopsy samples, and tumor-nodes-metastasis (TNM) staging. This study aimed to investigate the diagnostic performance of positron emission tomography/magnetic resonance imaging (PET/MRI) in vivo models for predicting low-vs-high lesion risk (LH) as well as biochemical recurrence (BCR) and overall patient risk (OPR) with machine learning.

METHODS

Fifty-two patients who underwent multi-parametric dual-tracer [18F]FMC and [68Ga]Ga-PSMA-11 PET/MRI as well as radical prostatectomy between 2014 and 2015 were included as part of a single-center pilot to a randomized prospective trial (NCT02659527). Radiomics in combination with ensemble machine learning was applied including the [68Ga]Ga-PSMA-11 PET, the apparent diffusion coefficient, and the transverse relaxation time-weighted MRI scans of each patient to establish a low-vs-high risk lesion prediction model (MLH). Furthermore, MBCR and MOPR predictive model schemes were built by combining MLH, PSA, and clinical stage values of patients. Performance evaluation of the established models was performed with 1000-fold Monte Carlo (MC) cross-validation. Results were additionally compared to conventional [68Ga]Ga-PSMA-11 standardized uptake value (SUV) analyses.

RESULTS

The area under the receiver operator characteristic curve (AUC) of the MLH model (0.86) was higher than the AUC of the [68Ga]Ga-PSMA-11 SUVmax analysis (0.80). MC cross-validation revealed 89% and 91% accuracies with 0.90 and 0.94 AUCs for the MBCR and MOPR models respectively, while standard routine analysis based on PSA, biopsy Gleason score, and TNM staging resulted in 69% and 70% accuracies to predict BCR and OPR respectively.

CONCLUSION

Our results demonstrate the potential to enhance risk classification in primary prostate cancer patients built on PET/MRI radiomics and machine learning without biopsy sampling.

Can the addition of clinical information improve the accuracy of PI-RADS version 2 for the diagnosis of clinically significant prostate cancer in positive MRI?

AIM

To report prostate cancer (PCa) prevalence in Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) categories and investigate the potential to avoid unnecessary, magnetic resonance imaging (MRI)-guided in-bore biopsies by adding clinical and biochemical patient characteristics.

MATERIALS AND METHODS

The present institutional review board-approved, prospective study on 137 consecutive men with 178 suspicious lesions on 3 T MRI was performed. Routine data collected for each patient included patient characteristics (age, prostate volume), clinical background information (prostate-specific antigen [PSA] levels, PSA density), and PI-RADS v2 scores assigned in a double-reading approach.

RESULTS

Histopathological evaluation revealed a total of 93/178 PCa (52.2%). The mean age was 66.3 years and PSA density was 0.24 ng/ml² (range, 0.04-0.89 ng/ml). Clinically significant PCa (csPCa, Gleason score >6) was confirmed in 50/93 (53.8%) lesions and was significantly associated with higher PI-RADS v2 scores (p=0.0044). On logistic regression analyses, age, PSA density, and PI-RADS v2 scores contributed independently to the diagnosis of csPCa (p=7.9×10^-7, p=0.097, and p=0.024, respectively). The resulting area under the receiver operating characteristic curve (AUC) to predict csPCa was 0.76 for PI-RADS v2, 0.59 for age, and 0.67 for PSA density. The combined regression model yielded an AUC of 0.84 for the diagnosis of csPCa and was significantly superior to each single parameter (p≤0.0009, respectively). Unnecessary biopsies could have been avoided in 50% (64/128) while only 4% (2/50) of csPCa lesions would have been missed.

CONCLUSIONS

Adding age and PSA density to PI-RADS v2 scores improves the diagnostic accuracy for csPCa. A combination of these variables with PI-RADS v2 can help to avoid unnecessary in-bore biopsies while still detecting the majority of csPCa.

P16INK4A immunohistochemistry for detection of human papilloma virus-associated penile squamous cell carcinoma is superior to in-situ hybridization

We evaluated p16INK4A as a reliable option to detect human papilloma virus (HPV) DNA in penile tumor specimens. Formalin-fixed paraffin embedded samples of 26 patients with penile cancer and another 18 cases with non-tumorigenic lesions were stained by three different widely used commercially available chromogenic in-situ hybridization assays high-risk HPV CISH Y1443 (Genpoint, DAKO), pan HPV CISH Y1404 (Genpoint, DAKO), INFORM HPV III (Ventana, Tucson, Arizona) and p16INK4A immunohistochemistry, then compared to the known gold standard polymerase chain reaction detecting HPV 16, 18, 31, and 33. Immunoreactivity for p16INK4A was evaluated by using a 4-tiered (0, 1, 2, and 3) pattern based system. 19 cases were positive for p16INK4A, 13 of which showed a continuous transepithelial staining (pattern 3). Pan HPV ISH showed positivity in 9 cases, high-risk HPV ISH in 7 cases and INFORM HPVIII ISH in 7 cases. p16INK4A IHC pattern 3 versus pattern 0, 1 and 2 exhibited a specificity and positive predictive value of 100 percent, with a sensitivity and negative predictive value of 72 and 62 percent, respectively, which was much better than all HPV in-situ hybridization methods referred to polymerase chain reaction. p16INK4A seems to be a superior marker for the detection of HPV-associated penile squamous cell carcinoma compared to CISH tests, but is not recommend for the detection of non-tumorigenic lesions, where PCR should be used for the initial assessment.

[Osteosarcoma of the prostate after radiotherapy]

Osteosarcoma of the prostate is a rare finding. These tumours usually occur years after radiotherapy for prostate cancer. We report the case of a 74-year-old man with prostate cancer who had been treated with radiotherapy and androgen deprivation therapy. The man presented with urinary retention and his prostate was transurethrally resected. The histopathological investigation showed formations of a poorly differentiated osteosarcoma in the prostate. Because of serious comorbidities we decided to withhold chemotherapy considering its potential side effects. The man died a few months after the diagnosis of osteosarcoma in the prostate with the disease in a metastatic stage. In conclusion, osteosarcoma of the prostate is a rarely reported consequence of radiotherapy in patients with prostate cancer and is characterised by poor life expectancy.

[Diagnostic of prostate cancer: conventional and molecular or cell biological methods]

At present the diagnosis of prostate cancer is carried out by transrectally obtained biopsy samples. The histological findings, the value for prostate-specific antigen (PSA) in the serum, and the clinical stage are the objective criteria for all subsequent therapy decisions. In over 95% of cases an acinar "usual" form of prostate cancer is diagnosed but can be very different in characteristics and differentiation. In order to correctly assess prostate cancer and to be able to select the best possible therapeutic measures resulting from the diagnosis, all information obtained from the biopsy must be used to a maximum. The demands on the optimal biopsy findings have considerably expanded in recent years. It must be able to obtain all additional biological, molecular and genetic findings from the biopsy material.

CD98hc (SLC3A2), a novel marker in renal cell cancer

BACKGROUND

In a variety of malignant diseases, molecular targeting represents a therapeutic option, whereby, when compared with chemotherapy, fewer side effects are thought to be expected. Especially in renal cell cancer (RCC), tyrosine kinase-inhibitors have been established as useful and highly effective therapy. However, tyrosine kinase-inhibitors currently approved for RCC treatment lack single molecule specificity and bear a variety of side effects of the gastro-intestinal tract, skin, heart and haematopoietic system. Therefore, the identification of novel cell surface markers is sought, which might lead to novel diagnostic and therapeutic strategies in cancer.

MATERIAL AND METHODS

Paraffin-embedded RCCs from a well characterized tissue bank were immunohistochemically quantified for embryonic transmembrane antigen CD98hc (SLC3A2) expression and semi-quantitative analyses were correlated with subtype or grade of differentiation.

RESULTS

We found increased CD98hc expression in different types of malign RCCs, among them clear cell (cc)RCC, papillary (p)RCC and chromophobe (ch)RCC, but lack of expression in the benign renal oncocytoma. Thereby, the extent of CD98hc expression directly complies with grade of malignancy. Furthermore, the more malignant type II pRCC significantly higher expressed CD98hc than the less malignant and more differentiated type I pRCC (type II 83.34%, type I 4.76% CD98hc positive, P < 0.00001; n = 51). The established marker for type I pRCC, Cytokreatin 7, showed 95.24% expression in type I and 26.67% expression in type II pRCC (P < 0.00001, n = 51).

CONCLUSIONS

From these data, we conclude that CD98hc is expressed in RCCs, whereby the extent of expression is likely to correlate directly with grade of malignancy. In pRCCs, CD98hc might represent a novel and reliable marker for type II pRCC.

Molecular-cytogenetic characterisation of sex cord-stromal tumours: CGH analysis in sertoli cell tumours of the testis

Sertoli cell tumours (SCT) are rare and poorly explored neoplasias, and the genetic features of these uncommon tumours are largely unknown. Data about chromosomal aberrations in human SCT of the testis are very rare. We present in this paper the first molecular-cytogenetic study of SCT of the testis. DNA was isolated from paraffin-embedded tumour material from 11 patients with unilateral SCT. We used comparative genomic hybridisation to investigate changes in DNA copy number. The detected DNA imbalances showed variation from case to case, indicating a high genetic heterogeneity. Chromosomal aberrations were detected in 9 of the 11 tumours evaluated, with 13 losses versus 14 gains. The most frequent aberrations detected were gain of chromosome X (5 of 11 cases) followed by losses of entire or part of chromosomes 2 and 19 in three cases. This study suggests a high variability in histomorphological and genetic patterns. Only gain of the entire chromosome X seems to be a frequent aberration in these tumours. Further studies of these tumour types are necessary to clarify the significance of chromosomal alterations in carcinogenesis of SCT.

Leydig cell tumors of the testis: a molecular-cytogenetic study based on a large series of patients

The genetic features of the uncommon Leydig cell tumors (LCT) are largely unknown. Consequently, it is of great importance to elucidate the pathogenesis of testicular germ cell tumors by cytogenetic and molecular biological investigations. The purpose of the present study was the examination of cytogenetic features of these tumors in a large series of LCT. It comprised formalin-fixed, paraffin-embedded tissue samples from 25 LCT to analyze the chromosomal constitution using comparative genomic hybridization (CGH). In most of the studied cases, the aberrant cell population was additionally defined by interphase fluorescence in situ hybridization (I-FISH). Our molecular-cytogenetic study indicates chromosomal imbalances in the majority of our cases (21/25, 84%). The most frequent findings were gain of chromosome X, 19 or 19p and loss on chromosome 8 and 16.

Flexible Cystoscopy Assisted by Hexaminolevulinate Induced Fluorescence: A New Approach for Bladder Cancer Detection and Surveillance?

OBJECTIVE

The aim of this study was the assessment of flexible cystoscopy assisted by hexaminolevulinate (HAL) fluorescence.

METHODS

This study was a prospective controlled, within-patient comparison of flexible HAL cystoscopy with standard flexible cystoscopy, HAL rigid and standard white light rigid cystoscopy. Eligible patients received an intravesical instillation of 50 ml hexylaminolevulinate 8 mM solution. First flexible than rigid cystoscopy was performed in each patient using a Combilight PDD system (Richard Wolf, Germany), which provided standard white light and blue light at 375 to 440 nm, with mapping of all lesions detected. All tumors and suspicious areas identified under white light and by red fluorescence with flexible or rigid cystoscopy were then resected by TUR or biopsied. The specimen was assessed by an independent blinded pathologist.

RESULTS

In the 45 patients studied 41 (91%) patients had exophytic tumors, of which 39 (95.1%) were detected by HAL flexible cystoscopy and 40 (97.5%) by HAL rigid cystoscopy. 17 (37.8%) patients had concomitant or carcinoma in situ only, which was identified by HAL flexible cystoscopy in 14 (82.3%), by HAL rigid cystoscopy in 15 (88.2%), by flexible standard in 11 (64.7%) and by standard white light rigid cystoscopy in 13 (76.7%) patients.

CONCLUSION

HAL fluorescence flexible cystoscopy compared to HAL rigid cystoscopy showed almost equivalent results in detecting papillary and flat lesions in bladder cancer patients. Both procedures were superior to standard white light flexible cystoscopy.

Cloning and molecular and immunological characterisation of two new food allergens, Cap a 2 and Lyc e 1, profilins from bell pepper (Capsicum annuum) and Tomato (Lycopersicon esculentum)

BACKGROUND

Profilins are recognised by IgE of about 20% of patients allergic to birch pollen and plant foods. They are ubiquitous intracellular proteins highly cross-reactive among plant species. Therefore, they were called panallergens and are made responsible for cross-sensitisation between plant pollen and food.

OBJECTIVES

The aim of the present study was to clone the cDNAs encoding profilins from bell pepper and tomato, to produce and purify the recombinant proteins and to compare their IgE-binding capacities to those of the natural proteins.

METHODS

cDNA clones coding for profilin were obtained by RT-PCR from total RNA of tomato and bell pepper fruits, sequenced and expressed as non-fusion proteins in ESCHERICHIA COLI. The recombinant profilins were subsequently purified and tested for IgE-binding and inhibition capacity with sera from 34 food-allergic patients. Possible oligomerisation of recombinant profilins was investigated by HPLC analysis and its influence on IgE binding assayed by ELISA.

RESULTS

The open reading frame from both profilins encompasses 393 bp with a predicted molecular mass of 14,184 kD and a pI of 4.44 for bell pepper profilin (Cap a 2) and 14,257 kD and a pI of 4.46 for the profilin from tomato (Lyc e 1). The two protein sequences display 91% identity, whereas tomato profilin from pollen shares only 75% identity with tomato fruit profilin. Eleven out of 34 food-allergic patients (32%) display IgE binding to both purified profilins. Preincubation of a serum pool with either purified rCap a 2 or rLyc e 1 nearly abolished IgE binding to natural Cap a 2 and Lyc e 1, respectively. In addition, purified recombinant Cap a 2 was able to inhibit IgE-binding to rLyc e 1 by approximately 50%, whereas rLyc e 1 completely blocked IgE-binding to rCap a 2 in cross-inhibition assays. HPLC analysis showed that in solution Cap a 2 and Lyc e 1 can be found predominantly as dimers, which can be partially reduced to monomers by addition of dithiothreitol (DTT). In ELISA DTT-treated Lyc e 1 displayed a clearly lower IgE-binding capacity than untreated profilin.

CONCLUSIONS

Purified rCap a 2 and rLyc e 1 proved to be valuable tools for studying cross-reactivity to profilins in patients allergic to pollen and food.

[Adenosquamous carcinoma of the palate]

A rare case of adenosquamous carcinoma in a 74 year-old man is reported. Presenting as a nodule on the soft palate, diagnosis was prolonged because of the benign macroscopic aspect. CT-scan and MR-tomography showed an encapsulated lesion but biopsy and histologic examination revealed the typical features of adenosquamous carcinoma. The tumour consisted of adenocarcinoma and squamous cell carcinoma in close proximity to minor salivary glands of which the tumour seemed to have its origin. This entity, although rare in the head and neck region has been documented to be very aggressive with early regional and hematogenic metastasis. Therefore it has to be distinguished from other tumours, especially from mucoepidermoid carcinomas of the salivary glands, which have a better prognosis. Adenosquamous carcinoma is considered to have poor radiosensitivity and chemotherapeutic approaches have also not been successful in the literature. In our case radical surgical therapy was performed by excision of the whole soft palate and bilateral neck dissection. This resulted in total removal of the tumour but revealed bilateral lymph node metastases. Vital functions were saved by reconstruction of the palate with a free vascularized tensor-fasciae-latae-perforator-flap. For the first time in a case of adenosquamous carcinoma carcinoembryonic antigen in serum was monitored. A pretherapeutical 29-fold elevation resulted in a marked decrease after surgery, but supranormal values indicated remaining tumour burden which was found in metastases in the lung. Because of the limitations in therapy, early histologic diagnosis is most important in this highly malignant tumour.

Morbidity of transrectal ultrasound-guided prostate needle biopsy in patients receiving immunosuppression

OBJECTIVES

To prospectively evaluate the safety and early and delayed morbidity of transrectal ultrasound-guided needle biopsies in patients receiving immunosuppressive therapy.

METHODS

A total of 59 men receiving immunosuppressive agents after kidney transplantation, with a total prostate-specific antigen level between 4 and 10 ng/mL, were prospectively studied. All patients underwent transrectal ultrasound (TRUS)-guided sextant biopsy plus two additional transition zone biopsies. Biopsy samples were also obtained from suspicious areas identified during TRUS and digital rectal examination. The immediate and delayed morbidity, patient satisfaction, and complication rates were recorded and compared with the morbidity data recorded in the same period from 1051 men in the European Prostate Cancer Detection study.

RESULTS

Of the 59 subjects, prostate cancer was detected in 17; 231 men were found to have cancer in the European Prostate Cancer Detection Study. Minor or no discomfort was observed in 88% and 92% of the transplant recipients and controls, respectively (P = 0.31). Twelve percent versus 8% experienced pain. Early morbidity included rectal bleeding (2.6% versus 2.1%, P = 0.19), severe hematuria (0.8% versus 0.7%, P = 0.08), and moderate to severe vasovagal episodes (1.9% versus 2.8%, P = 0.04). Late morbidity included fever (3.5% versus 2.9%, P = 0.1), hematospermia (11.0% versus 9.8%, P = 0.1), recurrent mild hematuria (17.4% versus 16.8%, P = 0.08), persistent dysuria (6.4% versus 7.2%, P = 0.2), and urinary tract infections (12.0% versus 10.9%, P = 0.08). Major complications were rare: urosepsis (0% versus 0.1%).

CONCLUSIONS

The results of our study demonstrate that TRUS-guided biopsy of the prostate is generally well tolerated, with minor morbidity, in patients receiving immunosuppression. No differences were noted in pain apprehension or early and delayed morbidity, suggesting that TRUS-guided biopsies can be performed safely in these patients.

Prospective evaluation of prostate cancer detected on biopsies 1, 2, 3 and 4: when should we stop?

PURPOSE

We evaluated biochemical parameters and pathological features, as well as biopsy related morbidity of prostate cancer detected on biopsies 2, 3 and 4 in men with total serum prostate specific antigen (PSA) between 4 and 10 ng./ml. These features were compared to those detected on prostate biopsy 1.

MATERIALS AND METHODS

In this prospective European Prostate Cancer Detection study 1,051 men with total PSA between 4 and 10 ng./ml. underwent transrectal ultrasound guided sextant biopsy and 2 additional transition zone biopsies. All patients in whom biopsy samples were negative for prostate cancer underwent biopsy 2 after 6 weeks. If also negative, biopsies 3 and even 4 were performed at 8-week intervals. Those patients with clinically localized cancer underwent radical prostatectomy. Pathological and clinical features of patients diagnosed with cancer on either biopsy 1 or 2 and clinically organ confined disease who agreed to undergo radical prostatectomy were compared.

RESULTS

Cancer detection rates on biopsies 1, 2, 3 and 4 were 22% (231 of 1,051), 10% (83 of 820), 5% (36 of 737) and 4% (4 of 94), respectively. Overall, of the patients with clinically localized disease, which was 67% of cancers detected, 86% underwent radical prostatectomy and 14% opted for watchful waiting or radiation therapy. Overall, 58.0%, 60.9%, 86.3% and 100% of patients had organ confined disease on biopsies 1, 2, 3 and 4, respectively. Despite statistically significant differences in regard to multifocality (p = 0.009) and cancer location (p = 0.001), including cancer on biopsy 2 showing a lower rate of multifocality and a more apico-dorsal location, there were no differences in regard to stage (p = 0.2), Gleason score (p = 0.3), percent Gleason grade 4/5 (p = 0.2), serum PSA and patient age between biopsies 1 and 2. However, cancer detected on biopsies 3 and 4 had a significantly lower Gleason score (p = 0.001 and 0.001), lower rate of grade 4/5 (p = 0.02), and lower volume (p = 0.001 and 0.001) and stage (p = 0.001), respectively.

CONCLUSIONS

Despite differences in location and multifocality, pathological and biochemical features of cancer detected on biopsies 1 and 2 were similar, suggesting comparable biological behaviors. Cancer detected on biopsies 3 and 4 had a lower grade, stage and volume compared with that on biopsies 1 and 2. Morbidity on biopsies 1 and 2 was similar, whereas biopsies 3 and 4 had a slightly higher complication rate. Therefore, biopsy 2 in all cases of a negative finding on biopsy 1 appears justified. However, biopsies 3 and 4 should only be obtained in select patients with a high suspicion of cancer and/or poor prognostic factors on biopsy 1 or 2.

Expression of the cell cycle proteins p21, p27, and pRb in clear cell renal cell carcinoma and their prognostic significance

OBJECTIVES

To determine whether p21, p27, and pRb can predict disease progression in clear cell renal cell carcinoma.

METHODS

The expression of three negative regulators of the cell cycle, the retinoblastoma gene product (pRb), the WAF1/Cip1 gene product (p21), and the Kip1 gene product (p27), was investigated by immunohistochemistry on paraffin sections from 104 formalin-fixed clear cell carcinoma specimens and related to p53 overexpression, the clinicopathologic parameters, and survival.

RESULTS

pRb expression was not associated with tumor stage, but the correlation with p27 and p21 positivity was statistically significant (r = 0.26, P = 0.008 and r = 0.3, P = 0.002, respectively). Tumors representing p53 overexpression showed a higher pRb labeling index compared with p53-negative tumors (P = 0.0004). p21 protein expression correlated significantly with p27 positivity (r = 0.2, P = 0.04) and was associated with p53 overexpression (P = 0.0005), but did not correlate with tumor stage or grade. No association could be found between p27 positivity and tumor grade, tumor stage, or p53 overexpression. In univariate survival analysis, an increased pRb positivity (P = 0.002) and a low p27 expression (P = 0.0001) predicted a poor outcome, especially if combined with p53 overexpression (P = 0.004 and P = 0.0002, respectively). p21 did not give any prognostic information. Moreover, in multivariate analysis, pRb and p27 were revealed to be statistically significant.

CONCLUSIONS

The results of our study indicate that in clear cell renal cell carcinoma, the cell cycle proteins p27 and pRb are powerful and independent prognostic factors and that p21 has no predictive value.

Genetic engineering of a hypoallergenic trimer of the major birch pollen allergen Bet v 1

An estimated 100 million individuals suffer from birch pollen allergy. Specific immunotherapy, the only curative allergy treatment, can cause life-threatening anaphylactic side effects. Here, we report the genetic engineering of a recombinant trimer consisting of three covalently linked copies of the major birch pollen allergen, Bet v 1. The trimer exhibited profoundly reduced allergenic activity but contained similar secondary structures such as Bet v 1 wild type, Bet v 1-specific B cell and T-cell epitopes, and induced Th1 cytokine release. As immunogen, rBet v 1 trimer induced IgG antibodies, which blocked patients' IgE binding to Bet v 1 and related allergens. Thus, rBet v 1 trimer represents a novel hypoallergenic vaccine prototype for treatment of one of the most frequent allergy forms.

Spatial distribution of prostate cancers undetected on initial needle biopsies

OBJECTIVES

The spatial distribution of cancer foci of prostate carcinomas with negative initial biopsies was compared to that of prostate carcinomas with positive initial biopsies to detect areas in which carcinomas were more frequently located when the initial biopsy was negative.

METHODS

Twenty patients with prostate cancer and a negative initial biopsy trial were detected among 218 patients with preceding systematic biopsies (9.2%) in our hospital. Analysis of the prostatectomy specimens regarding cancer distribution, multifocality, tumour size, Gleason score, and stage was performed using pathohistological techniques and three-dimensional computer reconstruction.

RESULTS

Prostatectomy specimens with negative initial biopsies showed more frequently cancer foci in apical (p<0.0001) and dorsal (p<0.02) prostatic compartments, higher incidence of multifocality (p<0.01), and smaller size of carcinoma foci (p<0.00003) compared to carcinomas in 81 stage-matched prostatectomy specimens with positive initial biopsies. Comparing both groups, no significant differences were noted in Gleason score of preoperative biopsies and prostatectomies, prostate weight, prostate-specific antigen (PSA) level, digital rectal examination, and patients age.

CONCLUSIONS

Missing the cancer in clinically significant prostate carcinomas by current systematic biopsy techniques may also be due to an apico-dorsal cancer location, particularly in combination with multifocality and small size of carcinoma foci in large prostates. In case of reasonable clinical suspicion of prostate cancer and negative initial biopsy, an early repeat biopsy with special emphasis on the apico-dorsal peripheral zone should be envisaged.

Bilharzial related, organ confined, muscle invasive bladder cancer: prognostic value of apoptosis markers, proliferation markers, p53, E-cadherin, epidermal growth factor receptor and c-erbB-2

PURPOSE

We investigated the association of the apoptosis related proteins Bcl-2, Bcl-x, Bax and Bak, p53, the adhesion molecule E-cadherin, the receptor proteins epidermal growth factor receptor and c-erbB-2, and the proliferation markers proliferating cell nuclear antigen and Ki-67 with the clinical outcome of bilharzial related transitional cell carcinoma and squamous cell carcinoma.

MATERIALS AND METHODS

Cystectomy specimens from 109 patients with organ confined, muscle invasive stage, pT2pN0M0, bilharziall positive bladder cancer were examined, including 60 with squamous cell carcinoma and 49 with transitional cell carcinoma. Immunohistochemical results were correlated with tumor progression.

RESULTS

In squamous cell carcinoma but not in transitional cell carcinoma the loss of epidermal growth factor receptor, Bax and Bak was significantly associated with higher histological grade (p = 0.02, 0.006 and 0.01, respectively). On univariate analysis patients with transitional cell carcinoma had a poorer prognosis than those with squamous cell carcinoma. p53 Over expression and the loss of Bak positivity were associated with shortened progression-free survival in transitional cell carcinoma (p = 0.006 and 0.04, respectively), and squamous cell carcinoma (p = 0.00001 and 0.04, respectively). In squamous cell carcinoma high tumor grade (p = 0.02) and in transitional cell carcinoma high labeling indexes for MIB-1, Bcl-x expression and c-erbB-2 positivity (p = 0.03, 0.02 and 0.04, respectively) were associated with a poorer prognosis. On multivariate analysis p53 emerged as a significant prognostic factor for each condition. Additional independent prognostic factors were proliferating cell nuclear antigen for squamous cell carcinoma, and MIB-1, Bcl-x and Bax for transitional cell carcinoma.

CONCLUSIONS

Bilharzial related transitional cell carcinoma and squamous cell carcinoma of the bladder differ in interims of protein expression and prognosis. Independent prognostic factors were p53, MIB-1, Bcl-x, and Bax in the former disease, and p53 and proliferating cell nuclear antigen in the latter disease.

Pathological features of prostate cancer detected on initial and repeat prostate biopsy: results of the prospective European Prostate Cancer Detection study

PURPOSE

We evaluated pathological features of prostate cancer detected on repeat prostate biopsy in men with a serum total prostate-specific antigen (PSA) level between 4 and 10 ng/ml who were diagnosed with benign prostatic tissue after an initial biopsy and compared them to those cancers detected on initial prostate biopsy.

MATERIALS AND METHODS

In this prospective European prostate cancer detection study, 1,051 men with a total PSA level between 4 and 10 ng/ml underwent transrectal ultrasound (TRUS)-guided sextant biopsy and two additional transition zone biopsies. All subjects whose biopsy samples were negative for prostate cancer (CaP) underwent a repeat biopsy after 6 weeks. Those with clinically localized cancers underwent radical prostatectomy. Pathological and clinical features of patients diagnosed with cancer on either initial or repeat biopsy and clinically organ confined disease who agreed to undergo radical prostatectomy were compared.

RESULTS

Initial biopsy was positive (CaP) in 231 of 1,051 enrolled subjects and negative (benign histology) in 820 subjects. Of these 820 subjects, CaP was detected in 10% (83/820) upon repeat biopsy. Of cancers detected on initial and repeat biopsy, 148/231 (64%) and 56/83 (67.5%) had clinically localized disease, respectively, and were offered radical prostatectomy. 10/148 (6.7%) and 3/56 (5.3%), respectively, opted for radiation therapy and thus, 138/148 (93.3%) and 53/56 (94.7%), respectively, underwent radical retropubic prostatectomy. There were statistically significant differences with respect to multifocality (P = 0.009) and cancer location (P < 0.001) with cancers on repeat biopsy showing a lower rate of multifocality and a more apico-dorsal location. In contrast, there were no differences with respect to stage (P = 0.2), Gleason score (P = 0.36), percentage Gleason grade 4/5 (P = 0.1), serum PSA (P = 0.62), and patient age (P = 0.517).

CONCLUSIONS

At least 10% of patients with negative prostatic biopsy results will be diagnosed with CaP on repeat biopsy. Despite differences in location and multifocality, pathological and biochemical features of cancers detected on initial and repeat biopsy are similar, suggesting similar biological behavior and thus advocating for a repeat prostate biopsy in case of a negative finding on initial biopsy. Cancers missed on initial biopsy and subsequently detected on repeat biopsy are located in a more apico-dorsal location. Repeat biopsies should thus be directed to this rather spared area in order to improve cancer detection rates.

Perimodiolar electrodes in cochlear implant surgery

Perimodiolar-positioned cochlear implant electrodes have been developed in order to bring the electrode contacts as close as possible to the spiral ganglion cells, which are the target of electrostimulation. This results in lower electrical thresholds, higher dynamic ranges and less channel interaction when compared with normal implant electrodes which are usually located peripherally within the scala tympani. In this study we evaluated 4 different types of perimodiolar electrode: the Clarion Preformed electrode, the Clarion Preformed electrode with positioner, the Nucleus Contour electrode and the Med-El Perimodiolar Combi 40 electrode. These devices require different approaches to achieve a perimodiolar electrode position. The electrodes were inserted in fresh human temporal bones. After processing these bones with the electrodes in situ by employing a sawing, grinding and polishing technique, the inner ear structures as well as the electrode positions could be evaluated in detail. All electrode types studied had a more or less perimodiolar position; however, each type produced a certain amount of trauma to cochlear structures which is discussed in relation to mechanical properties. Further human temporal bone studies with improved perimodiolar cochlear implant electrodes are necessary in order to find an optimized type of electrode.

Hev b 9, an enolase and a new cross-reactive allergen from hevea latex and molds. Purification, characterization, cloning and expression

Natural rubber latex allergy is an IgE-mediated disease that is caused by proteins that elute from commercial latex products. A complementary DNA (cDNA) coding for Hev b 9, an enolase (2-phospho-D-glycerate hydrolyase) and allergen from latex of the rubber tree Hevea brasiliensis, was amplified by PCR. The PCR primers were designed according to conserved regions of enolases from plants. The obtained cDNA amplification product consisted of 1651 bp and encoded a protein of 445 amino-acid residues with a calculated molecular mass of 47.6 kDa. Sequence comparisons revealed high similarities of the Hevea latex enolase to mold enolases that have been identified as important allergens. In addition, the crucial amino-acid residues that participate in the formation of the catalytic site and the Mg2+ binding site of enolases were also conserved. Hevea latex enolase was produced as a recombinant protein in Escherichia coli with an N-terminal hexahistidyl tag, and purified by affinity chromatography. The yield amounted to 110 mg of purified Hev b 9 per litre of bacterial culture. The recombinant allergen bound IgE from latex, as well as mold-allergic patients, in immunoblot and ELISA experiments. The natural enolase was isolated from Hevea latex by (NH4)2SO4 precipitation and ion exchange chromatography. The natural and the recombinant (r)Hev b 9 showed equivalent enzymatic activity. Patients' IgE-antibodies preincubated with rHev b 9 lost their ability to bind to natural (n) Hev b 9, indicating the identity of the B-cell epitopes on both molecules. Cross-reactivity with two enolases from Cladosporium herbarum and Alternaria alternata was determined by inhibition of IgE-binding to these enolases by rHev b 9. Therefore, enolases may represent another class of highly conserved enzymes with allergenic potentials.

IgE-binding epitopes of enolases, a class of highly conserved fungal allergens

BACKGROUND

Cladosporium herbarum and Alternaria alternata are two of the most prominent fungal species inducing type I allergy. Previously, we have demonstrated that enolase (Cla h 6) is the second most important allergen of C herbarum in terms of frequency of sensitization.

OBJECTIVE

IgE-reactive B-cell epitopes of C herbarum enolase were analyzed, and cross-reactivity between fungal enolases was investigated.

METHODS

Cla h 6 glutathione-S-transferase fusion peptides were constructed by means of PCR cloning. A alternata enolase (Alt a 5) was isolated by screening a complementary (c)DNA expression library with a C herbarum enolase DNA probe.

RESULTS

Mapping of Cla h 6 IgE-binding epitopes identified a peptide with a length of 69 amino acids (peptide 9), which bound IgE from 8 of 8 patients. Analysis of the conformation of peptide 9 revealed that it does not form a compact structure but rather spans the whole length of the protein, with side chains exposed to solvent at 3 locations. Peptide 9 in the context of Escherichia coli glutathione-S-transferase not only binds IgE but also competitively inhibits IgE binding to Alt a 5. This result indicates that the epitope or epitopes on peptide 9 constitute a major cross-reacting epitope or epitopes on the enolases from C herbarum and A alternata in the case of the one patient tested.

CONCLUSIONS

We demonstrated that the glycolytic enzyme enolase is an allergen not only in C herbarum but also in A alternata. Additionally, enolase was shown to exhibit high cross-reactivity to other fungal enolases. On the basis of the results presented here, we propose the use of recombinant Cla h 6 or maybe even peptide 9 of Cla h 6 for diagnosis and possibly therapy of mold allergy.

Transcutaneous high-intensity focused ultrasound and irradiation: an organ-preserving treatment of cancer in a solitary testis

OBJECTIVES

The aim of this study was to determine the feasibility and safety of transcutaneous ablation of human testicular tissue by high-intensity focused ultrasound (HIFU).

METHODS

Transcutaneous ablation of human testicular tissue by HIFU was performed with equipment previously developed for transrectal prostate ablation. This device utilizes a piezoceramic transducer operating at 4.0 MHz with a site-intensity of 1,600-2,000 W/cm2. To study the histological impact of transcutaneous HIFU, tests of 4 patients with prostate cancer were subjected to transcutaneous HIFU-therapy prior to scrotal orchiectomy in a phase I trial. In a phase II clinical trial, 4 patients with the typical sonographic pattern of a tumor in a solitary testis were treated with transcutaneous HIFU as a minimally invasive organ-preserving approach followed by a 6 weeks' course of prophylactic irradiation of the testis with 20 Gy. In all 4 patients, the contralateral testis had been previously removed for testis cancer.

RESULTS

Histologically, HIFU-treated areas exhibited signs of cellular necrosis in all cases (n = 4). The border between viable and necrotic tissue was extremely sharp comprising only 5-7 cell layers. In the phase II clinical study, we aimed to ablate the entire cancer in a single therapeutic HIFU session. HIFU treatment was performed under general anesthesia. As negative side effects we observed a cutaneous thermolesion in 1 individual. One patient refused to undergo postoperative irradiation and developed a local failure. This patient underwent radical orchiectomy. Another patient received two cycles of chemotherapy for a single suspicious retroperitoneal lymph node diagnosed 6 months after HIFU therapy. Three patients are tumor-free with a follow-up of 16, 23 and 31 months, respectively.

CONCLUSIONS

This study demonstrates the feasibility and safety of transcutaneous testicular tissue ablation by HIFU. Despite the major drawback of this technique, i.e. that no tumor histology is obtained, we believe that transcutaneous HIFU followed by irradiation has the potential to be established as a minimally invasive treatment alternative to organ-preserving surgery for tumors in a solitary testis.

Renal oncocytoma with prominent intracytoplasmic vacuoles of mitochondrial origin

AIMS

We observed two oncocytomas with prominent intracytoplasmatic vacuoles. To investigate if this previously undescribed finding is a diagnostic feature and compatible with the diagnosis of oncocytoma, we characterized these vacuoles by electron microscopy and immunohistochemistry.

METHODS AND RESULTS

The tumours were analysed by transmission electron microscopy. Immunohistochemistry was performed with antimitochondrial antibody, anti-Golgi-zone antibody, anti-lysozyme antibody and anti-human-trans-Golgi-network antibody. By electron microscopy, the vacuoles were found to be double-membrane-bounded, and some contained fragmented christae. Immunohistochemistry showed a positive reaction of the vacuoles with anti-mitochondrial antibody. Staining with anti-Golgi-zone antibody, anti-lysozyme antibody and anti-human-trans-Golgi-network antibody was negative.

CONCLUSION

Both tumours are benign oncocytomas. The phenomena of cells with prominent intracytoplasmatic vacuoles is not inconsistent with the diagnosis of oncocytoma. The vacuoles are of mitochondrial origin and may develop, by balloon degeneration, as a mechanism of mitochondrial involution and elimination.

Gastric perforation of a left lobe amoebic liver abscess

Liver abscess is the most common extra-intestinal manifestation of invasive amoebiasis. Perforation of the abscess is a potential life-threatening complication. We report a case where perforation into the stomach was successfully managed conservatively. The initial diagnosis in this case was made by gastroscopy and biopsy. To our knowledge, only five cases of gastric perforation of an amoebic liver abscess have been reported in the English literature. In none of these cases was the diagnosis established by histology of gastric biopsy specimens.

Expression of the VEGF-receptor Flt-1 in benign, premalignant and malignant prostate tissues

PURPOSE

Vascular endothelial growth factor (VEGF) is one of the most potent regulators of angiogenesis and has been shown to act upon two tyrosine kinase family receptors: c-fms-like tyrosine kinase (Flt-1) and fetal liver kinase. Preliminary reports have emphasized that expression of VEGF receptors is endothelial cell-specific. In this study we verified the localization and distribution of Flt-1 protein and mRNA expression in prostatic adenocarcinoma (CaP) as well as prostate intraepithelial neoplasia (PIN) and benign prostatic hyperplasia (BPH).

MATERIALS AND METHODS

30 selected surgical specimens exhibiting areas with CaP, PIN and BPH histology were evaluated for Flt-1 protein expression by immunohistochemistry. Results were compared with tumor differentiation (Gleason-Score), serum-PSA and clinical followup. Flt-1 synthesis by prostatic carcinoma cell lines, freshly isolated BPH epithelial cells (BPH-EC) and stromal cells was investigated using RT-PCR and intron spanning primer.

RESULTS

VEGF receptor Flt-1 specific anti-sera revealed significant staining of prostatic endothelial cells, but the reactivity was not restricted to endothelial cells. BPH-epithelial cells of all specimens reacted significantly with anti-Flt-1. In contrast, tumor cells failed to react with anti-Flt-1 in 56% of the specimens. BPH-EC revealed a uniform anti-Flt-1 reactivity, which was less pronounced and weaker in PIN. Loss of anti-Flt-1 reactivity of prostatic tumor cells did not correlate with preoperative PSA serum levels but increased with tumor dedifferentiation. Interestingly, tumor cells of all CaP specimens with a Gleason score of >8 exhibit no anti-Flt-1 immunoreactivity. Accordingly while PC3, DU145 and LNCaP cells were negative when tested using RT-PCR all BPH tissue derived BPH-EC revealed Flt-1 coding mRNA expression.

CONCLUSIONS

Widespread distribution of VEGF receptor Flt-1 in BPH, PIN and prostate cancer specimens suggests that VEGF function in prostate is not restricted to endothelial cells and angiogenesis. However, since the receptor is lost in CaP cells and with tumor dedifferentiation, these yet unknown effects of VEGF on epithelial cells are obviously suppressed with malignant transformation.

Capillary haemangioma of the testis

A case of testicular capillary haemangioma is reported and the importance of intraoperative examination of this very rare lesion emphasised. Capillary haemangioma of the testis can be similar to malignant testicular tumours on clinical presentation, as well as on ultrasonography and magnetic resonance imaging, and therefore should be included in the intraoperative differential diagnosis. Because of the benign nature of this lesion, conservative surgical treatment by means of tumour enucleation with preservation of the testis is possible, if intraoperative examination of frozen sections of representative tissue can be performed.

Soft-tissue effects of the holmium:YAG laser: an ultrastructural study on oral mucosa

BACKGROUND AND OBJECTIVE

The specifics of the ablation mechanism of the holmium:YAG laser remain largely unexplored. Following laser exposure to the oral mucosa of rats, the ultrastructural damage profile obtaining to varying degrees in blood vessels, erythrocytes, nerves, and muscle cells was examined. An attempt was made to relate the cytoplasmatic alterations to the tissue ablation modes of midinfrared lasers described in the literature.

STUDY DESIGN/MATERIALS AND METHODS

The biological effects of a new pulsed holmium:YAG laser (lambda = 2,120 nm) on the oral mucosa of rats were examined by light and transmission electron microscopy. Laser incisions reaching into the muscle layer were made on different sites of the tongue of white rats. Laser energy (400 mJ, 2.5 microseconds pulse, 2 Hz) was delivered to the target via 400 microns nylon fibers.

RESULTS

The fine-structural morphology of the sublingual mucosa after laser surgery of the epithelial surface revealed no carbonization layer but a 150-micron-wide zone of lacunar structures extending to the lamina propria. In the muscle cells there is partial decomposition of the cell contents resulting in the development of electron optically empty spaces within the cortical cytoplasm underneath the intact plasma membrane of the muscle cell. The organelles within the cell remain ultrastructurally intact.

CONCLUSION

These features support the assumption of an additional nonthermal holmium:YAG laser-tissue interaction.

[Intracochlear position of cochlear implant electrodes]

The insertion of cochlear implant electrodes in human temporal bones may be associated with the destruction of structures within the cochlea. The aim of this study was to measure such insertional trauma by means of histologic processing of implanted human temporal bones following implantation of a Combi 40/40+ electrode array (Med-El, Innsbruck). We implanted 6 human temporal bones with original electrodes (3 with Combi 40 and 3 with Combi 40+). In 4 bones Healon was used for electrode insertion. The histological investigation was performed after radiographic evaluation of the position of the electrode. For the histological procedure we used a technique which keeps the electrodes in position within the cochlea. In these slides we could clearly identify the electrodes in the tympanic scale. When inserted properly (point of first resistance) no trauma occurred in the basal portion of the cochlea and minimal trauma in the middle portion of the cochlea.

mdm2 expression as a prognostic indicator in clear cell renal cell carcinoma: comparison with p53 overexpression and clinicopathological parameters

The present study was designed to analyze the expression of p53 and mdm2 in clear cell renal cell carcinoma with special emphasis on their association with tumor grade and clinical outcome. In particular, the value of individual protein overexpression as well as combined p53/mdm2 positivity was evaluated because both proteins are functionally connected, and their expression is controlled by an autoregulatory feedback loop. A cohort of 97 clear cell renal cell carcinomas was analyzed. The overexpression of mdm2 and p53 proteins was investigated on paraffin-embedded material by using monoclonal antibodies. Eighteen tumors showed mdm2 positivity, whereas 35 of the tumors overexpressed p53. Whereas p53 and mdm2 positivity correlated significantly (P = 0.00004), no correlation could be found between mdm2 protein overexpression and tumor stage, lymph node involvement, and presence of distant metastases. mdm2 positivity was found significantly more frequently in tumors of higher grade. In univariate analysis, there was a statistically significant correlation between p53 and mdm2 overexpression in the same tumor and poor survival (P = 0.00179). Multivariate analysis revealed that coincident mdm2/p53 overexpression, the presence of distant metastases, and tumor grade were independent predictors for tumor progression. Our results indicate that mdm2/p53 co-overexpression, nuclear grade, and preoperative presence of distant metastasis are independent predictors for poor survival.

Quick-staining urinary cytology and bladder wash image analysis with an integrated risk classification: a worthwhile improvement in the follow-up of bladder cancer?

BACKGROUND

With an end toward an increase in patient quality of life, morphologic methods were tested for their combinatory value in expanding the effectiveness of follow-up appointments and finding a more specific supervision of patients with bladder cancer.

METHODS

Voided urine and bladder washing specimens were gathered in 223 follow-up sessions of 124 patients with a history of bladder cancer. Hemacolor (Merck, Darmstadt, Germany)-stained cytospin preparations of voided urine specimens were ready for diagnosis within 15 minutes, and results were available shortly before cystoscopy. Feulgen-Schiff-stained cytospin preparations of bladder washings entered the image analysis system. A special software was used to classify the DNA histogram by a risk factor for bladder cancer.

RESULTS

Follow-up of patients revealed 83 tumor recurrences. Depending on the grade of the underlying tumor, the sensitivity of quick-staining cytology was 86.4%, 46.2%, or 13.6% for grade 3 to grade 1 TCC, respectively. Cytology and image analysis data demonstrated complementary potency. The combination of methods increased sensitivity to 90.9%, 66.7%, and 31.8%, respectively. Although 24 of 140 image analyses denoted high risk for bladder cancer without simultaneously visible tumor, correct evidence of high risk could be found for 92.2%.

CONCLUSIONS

The combinatory use of quick-staining urinary cytology and bladder wash image analysis was demonstrated to be most valuable in diagnosing recurrent bladder cancer and selecting patients needing more intensive follow-up. At a minimum of patients discomfort, the tested combination also seems helpful to surpass diagnostic limits in cystoscopy and cytology caused by therapeutic effects on the bladder epithelium. Cancer (Cancer Cytopathol)

Tyrosine kinases expressed in vivo by human prostate cancer bone marrow metastases and loss of the type 1 insulin-like growth factor receptor

An important biological feature of prostate cancer (PCa) is its marked preference for bone marrow as a metastatic site. To identify factors that may support the growth of PCa in bone marrow, expression of receptor and nonreceptor tyrosine kinases by androgen-independent PCa bone marrow metastases was assessed. Bone marrow biopsies largely replaced by PCa were analyzed using reverse transcriptase-polymerase chain reaction amplification with degenerate primers that amplified the conserved kinase domain. Sequence analyses of the cloned products demonstrated expression of multiple kinases. Expression of the receptor and nonreceptor tyrosine kinases, alpha platelet-derived growth factor receptor and Jak 1, respectively, was confirmed by immunohistochemistry. In contrast, the type 1 insulin-like growth factor receptor, thought to play a role in PCa development, was lost in metastatic PCa. These results implicate several specific growth factors and signaling pathways in metastatic androgen-independent PCa and indicate that loss of the type 1 insulin-like growth factor receptor contributes to PCa progression.

Predictability and significance of multifocal prostate cancer in the radical prostatectomy specimen

Multifocal prostate cancer has been reported in 50-76% of all cases of radical retropubic prostatectomy (RRP) specimens, but the clinical and prognostic significance of this finding is still unclear. A retrospective analysis of patients who underwent RRP between 1993 and 1997 was performed. Preoperative screening parameters and 4-mm RRP specimen sections were examined. The location, Gleason score, and extracapsular extension of the tumor recorded. Three hundred eight cases were reviewed. Mean follow-up was 4.2 +/- 1 years (range 2-6 years). Two hundred six patients (66.9%) had multifocal prostate cancer and 102 (33.1%) had unifocal prostate cancer. Of those with multifocal disease, 63% had two foci and 37% had three or more foci. There were statistical significant differences between both groups with respect to preoperative prostate-specific antigen (PSA) density of the transition zone (PSA-TZ), free/total (f/t) PSA, as well as percentage of patients with organ confined disease, high-grade tumors, and local recurrence. PSA-TZ (p = .001) and f/t PSA (p = .004) were significantly different between patients with unifocal and multifocal disease (0.9 vs. 2.2 ng/mL/cc and 18% vs. 6.5%, respectively). However, preoperative PSA (11.2 vs. 12.8 ng/mL; p = .09) and PSA density (0.17 vs. 0.19 ng/mL/cc; p = .07) were not able to predict unifocality or multifocality. These data suggest that multifocal prostate cancer is associated with higher grade, stage, and recurrence rate than unifocal prostate cancer. Preoperative PSA-TZ (> 1.5 ng/mL/cc) and f/t PSA (<9%) may predict multifocality in the RRP specimen.

Biologic behavior of and p53 overexpression in multifocal renal cell carcinoma of clear cell type: an immunohistochemical study correlating grading, staging, and proliferation markers

BACKGROUND

In the treatment of small renal cell carcinoma (RCC), there is controversy between radical and nephron-sparing surgical treatment because of the risk of tumor multifocality. The biologic behavior of multifocal RCC compared with that of unifocal RCC is not well investigated, and the relevance of p53 and the proliferation markers MIB-1 and proliferating cell nuclear antigen (PCNA) to multifocal RCC is not yet established.

METHODS

In this study, p53 protein overexpression was investigated immunohistochemically in 27 multifocal and 65 unifocal clear cell RCCs using a monoclonal antibody (DO-1). The nuclear expression of p53 was compared with the expression of PCNA and MIB-1 (Ki-67 antigen) and other prognostic factors, including grade and stage.

RESULTS

Thirty-three RCCs (35.9%) had p53 positive nuclear staining. MIB-1 positivity was significantly higher in p53 positive tumors than in p53 negative tumors. PCNA positivity was not different in p53 positive tumors compared with p53 negative tumors. Proliferation marker expression was not associated with tumor focality. p53 overexpression was more often found in unifocal tumors than in multifocal tumors. Intracellular accumulation of the p53 protein was related to tumor grade but not to the T classification of tumor stage. In addition, lymph node involvement was significantly associated with p53 overexpression in tumors of the kidney. Focality did not influence progression free survival.

CONCLUSIONS

This study demonstrated that there is no difference in the proliferative activity or biologic behavior of multifocal and unifocal tumors.

Biologic behavior of and p53 overexpression in multifocal renal cell carcinoma of clear cell type: an immunohistochemical study correlating grading, staging, and proliferation markers

BACKGROUND

In the treatment of small renal cell carcinoma (RCC), there is controversy between radical and nephron-sparing surgical treatment because of the risk of tumor multifocality. The biologic behavior of multifocal RCC compared with that of unifocal RCC is not well investigated, and the relevance of p53 and the proliferation markers MIB-1 and proliferating cell nuclear antigen (PCNA) to multifocal RCC is not yet established.

METHODS

In this study, p53 protein overexpression was investigated immunohistochemically in 27 multifocal and 65 unifocal clear cell RCCs using a monoclonal antibody (DO-1). The nuclear expression of p53 was compared with the expression of PCNA and MIB-1 (Ki-67 antigen) and other prognostic factors, including grade and stage.

RESULTS

Thirty-three RCCs (35.9%) had p53 positive nuclear staining. MIB-1 positivity was significantly higher in p53 positive tumors than in p53 negative tumors. PCNA positivity was not different in p53 positive tumors compared with p53 negative tumors. Proliferation marker expression was not associated with tumor focality. p53 overexpression was more often found in unifocal tumors than in multifocal tumors. Intracellular accumulation of the p53 protein was related to tumor grade but not to the T classification of tumor stage. In addition, lymph node involvement was significantly associated with p53 overexpression in tumors of the kidney. Focality did not influence progression free survival.

CONCLUSIONS

This study demonstrated that there is no difference in the proliferative activity or biologic behavior of multifocal and unifocal tumors.

The importance of recombinant allergens for diagnosis and therapy of IgE-mediated allergies

In the past 10 years, a considerable number of cDNAs coding for allergens have been isolated and expressed. Intensive investigations showed that recombinant allergens and their respective natural counterparts possess comparable properties with respect to structure, function and interaction with the immune system. Recent studies documented that in vitro as well as in vivo diagnosis of IgE-mediated allergic diseases can be successfully improved by the application of recombinant allergens. In addition, new strategies for a safer specific immunotherapy (SIT) have been developed based on the knowledge of the primary structures of allergens. Naturally occurring isoforms of allergens as well as recombinant allergens with modified amino acid sequences show very low IgE binding capacity but strong T cell-stimulatory activity and represent possible candidates. In case of Bet v 1, the major birch pollen allergen, isoforms d, g and l and a Bet v 1a mutant, produced by site-directed mutagenesis resulting in 6 amino acid exchanges, fulfilled the above mentioned criteria. In a third approach, two adjacent peptides covering the entire Bet v 1a sequence were produced in an Escherichia coli expression system. These peptides contained most of the relevant T cell epitopes, but lost their IgE binding capacity and, thus, their ability to activate mast cells and basophils of sensitized patients. Our results suggest that allergen variants (isoforms, mutants, T cell epitope-containing peptides) may be used as 'hypoallergenic agents' in SIT.

Expression of bcl-2, bcl-x, bax and bak in renal parenchyma, oncocytomas and renal cell carcinomas

Proteins of the bcl-2 family are important regulators of programmed cell death. Alterations in the expression of these proteins may contribute to the progression of cancer. Expression of bcl-2, bcl-x, bax and bak was investigated by immunohistochemistry and Western-blotting of regular and alterated renal parenchyma as well as in 57 renal cell carcinomas. Bcl-2, bcl-x and in part bax were found to be overexpressed in inflammed renal parenchyma, whereas atrophic tubuli predominantly stained for bcl-2 and to a lesser degree for bcl-x and bax. Only little bak expression was detected in alterated tubuli. Moderate to strong expression for bcl-2, bcl-x, bax and bak was found in 24, 38, 2 and 13 of 57 carcinomas, respectively. Bcl-2, bcl-x, bax and bak expression were correlated to tumor type. Chromophilic carcinomas stained stronger for bcl-2, bcl-x and bax, whereas chromophobic carcinomas stained stronger for bcl-x, bax and bak compared to clear cell carcinomas. Expression of bak correlated with that of bcl-x and with an unfavorable histology as indicated by nuclear grading in these tumors. Our findings suggest that expression of bcl-2 and bcl-x may be important for cell survival only in a subset of renal cell carcinomas, and that the anti-apoptotic effect of these proteins appears to be frequently bypassed possibly by other factors impeding programmed cell death.

Prostate specific antigen density of the transition zone for predicting pathological stage of localized prostate cancer in patients with serum prostate specific antigen less than 10 ng./ml

PURPOSE

Prostate specific antigen (PSA) density of the transition zone, which is the density of serum PSA related to the volume of the transition zone, has been recently demonstrated to enhance prostate cancer prediction in patients with intermediate PSA levels. We further investigated the usefulness of PSA-transition zone for predicting extraprostatic extension in clinically localized prostate cancer.

MATERIALS AND METHODS

Measuring the transition zone of the prostate by ultrasound using the prolate ellipsoid method, PSA-transition zone values were calculated prospectively in 198 patients with clinically localized prostate cancers and serum PSA less than 10.0 ng./ml. who underwent radical retropubic prostatectomy. The ability of PSA-transition zone to predict extracapsular disease in the surgical specimen was compared to Gleason score, serum PSA, PSA density of the total prostate and percent free PSA using univariate or multivariate analysis as well as receiver operating characteristics curves.

RESULTS

A total of 104 patients (52.5%) had pathologically organ confined prostate cancer while 94 of 198 (47.5) had extracapsular disease. PSA-transition zone levels were significantly higher in extracapsular disease than organ confined cancers (0.84 versus 0.42 ng./ml./cc, p <0.00001). Using multivariate analyses PSA-transition zone and Gleason score were the most significant predictors of extracapsular disease. The area under the curve was larger for PSA-transition zone (0.825) than any other parameter (p <0.004 versus PSA density and p <0.001 versus PSA, percent free PSA or Gleason score). A cutoff of 1.00 ng./ml./cc for PSA-transition zone provided 95.1% specificity and 28.8% sensitivity for predicting extracapsular disease. Probability plots using the best combination of independent variables for predicting extraprostatic extension were developed.

CONCLUSIONS

These data demonstrate that the use of the PSA-transition zone may be of additional value for indicating which patients with clinically localized prostate cancer and PSA less than 10.0 ng./ml. are at high risk for extracapsular disease.

Transperineal radiofrequency interstitial tumor ablation (RITA) of the prostate

The purpose of this study was to investigate the safety and feasibility of radiofrequency interstitial tumor ablation (RITA) in localized prostate cancer (PCa) and to assess the predictability of the lesions obtained. In 10 patients with localized PCa (mean age 70.4 years), a total of 21 marker lesions were induced under general (n = 3), spinal (n = 4), or local anesthesia only (n = 3). Radiofrequency energy was delivered transperineally under transrectal ultrasound (TRUS) guidance. Radical prostatectomy was performed in all patients 1-7 days after RITA. The findings of intraoperative TRUS and histologic examination of the specimen were correlated. Lesions 2 x 2 x 2 cm were targeted. Postoperatively, patients were catheterized for an average of 1.8 days (range 1-3). Average lesion diameters defined by coagulative necrosis at histologic examination were 2.20 +/- 0.23 x 2.10 +/- 0.31 x 2.38 +/- 0.14 cm (average volume 5.86 +/- 1.63 cm3). Lesions were well defined and did not extend beyond the prostatic capsule. No complications (e.g., rectal wall injury) were noted. RITA-induced lesions were safe, feasible, technically simple, and resulted in lesions well predictable in size and location. On histologic examination, well-defined areas of coagulative necrosis were documented. No damage to the periprostatic tissue was noted. The procedure can be performed with spinal or local anesthesia only.

N-acetylneuraminic acids (nana): a potential key in renal calculogenesis

N-Acetylneuraminic acids (NANA) promote binding of calcium ions to macromolecules and cells, increase the intrinsic viscosity of glycoproteins and facilitate gel formation in water. Since these properties are crucial in urinary calculogenesis, we evaluated NANA levels in urine and serum as well as their expression in kidney tissues. Using a modified thiobarbituric acid assay, the evaluation of free and bound NANA in 24-h urine samples revealed a ratio of 1.87 in 33 non-stone-formers but a reversed ratio of 0.84 in 41 recurrent calcium oxalate stone-formers. Time kinetics revealed a gradual rise in NANA expression until 48 h of culture and a significantly higher release into supernatants of papillary renal epithelial cells (REC) when compared with cortical REC. To examine NANA distribution in kidney tissues, paraffin-embedded biopsies from five normal and six stone-forming kidneys were labeled with the biotinylated NANA-specific lectins Maackia amurensis (MAA) and Sambucus nigra (SNA). Immunohistochemistry revealed intense luminal MAA reactivity of distal tubular REC and collecting ducts in 96.7% and 91.5% of normal and stone-forming kidneys respectively. By contrast, there was a marked difference between normal and stone-forming kidneys for SNA reactivity (17.7% vs 95%) at the same locations. Finally, the glycocalyx of recurrent stone-formers showed altered sialylglycoside linkages [alpha(2,6) instead of alpha(2,3)] that may indicate an altered REC function. Given the calcium-binding potential of NANA, their increased local concentration within the glycocalyx layer in the distal nephron may either initiate stone formation or facilitate attachment of microcrystals to REC.