Andreas Erbersdobler

The Contemporary Concept of Significant Versus Insignificant Prostate Cancer

CONTEXTnThe notion of insignificant prostate cancer (Ins-PCa) has progressively emerged in the past two decades. The clinical relevance of such a definition was based on the fact that low-grade, small-volume, and organ-confined prostate cancer (PCa) may be indolent and unlikely to progress to biologic significance in the absence of treatment.nnnOBJECTIVEnTo review the definition of Ins-PCa, its incidence, and the clinical impact of Ins-PCa on the contemporary management of PCa.nnnEVIDENCE ACQUISITIONnA review of the literature was performed using the Medline, Scopus, and Web of Science databases with no restriction on language up to September 2010. The literature search used the following terms: insignificant, indolent, minute, microfocal, minimal, low volume, low risk, and prostate cancer.nnnEVIDENCE SYNTHESISnThe most commonly used criteria to define Ins-PCa are based on the pathologic assessment of the radical prostatectomy specimen: (1) Gleason score ≤ 6 without Gleason pattern 4 or 5, (2) organ-confined disease, and (3) tumour volume<0.5 cm(3). Several preoperative criteria and prognostication tools for predicting Ins-PCa have been suggested. Nomograms are best placed to estimate the risk of progression on an individualised basis, but a substantial proportion of men with a high probability of harbouring Ins-PCa are at risk for pathologic understaging and/or undergrading. Thus, there is an ongoing need for identifying novel and more accurate predictors of Ins-PCa to improve the distinction between insignificant versus significant disease and thus to promote the adequate management of PCa patients at low risk for progression.nnnCONCLUSIONSnThe exciting challenge of obtaining the pretreatment diagnostic tools that can really distinguish insignificant from significant PCa should be one of the main objectives of urologists in the following years to decrease the risk of overtreatment of Ins-PCa.

Targeting Activin Receptor-Like Kinase 1 Inhibits Angiogenesis and Tumorigenesis through a Mechanism of Action Complementary to Anti-VEGF Therapies

Genetic and molecular studies suggest that activin receptor-like kinase 1 (ALK1) plays an important role in vascular development, remodeling, and pathologic angiogenesis. Here we investigated the role of ALK1 in angiogenesis in the context of common proangiogenic factors [PAF; VEGF-A and basic fibroblast growth factor (bFGF)]. We observed that PAFs stimulated ALK1-mediated signaling, including Smad1/5/8 phosphorylation, nuclear translocation and Id-1 expression, cell spreading, and tubulogenesis of endothelial cells (EC). An antibody specifically targeting ALK1 (anti-ALK1) markedly inhibited these events. In mice, anti-ALK1 suppressed Matrigel angiogenesis stimulated by PAFs and inhibited xenograft tumor growth by attenuating both blood and lymphatic vessel angiogenesis. In a human melanoma model with acquired resistance to a VEGF receptor kinase inhibitor, anti-ALK1 also delayed tumor growth and disturbed vascular normalization associated with VEGF receptor inhibition. In a human/mouse chimera tumor model, targeting human ALK1 decreased human vessel density and improved antitumor efficacy when combined with bevacizumab (anti-VEGF). Antiangiogenesis and antitumor efficacy were associated with disrupted co-localization of ECs with desmin(+) perivascular cells, and reduction of blood flow primarily in large/mature vessels as assessed by contrast-enhanced ultrasonography. Thus, ALK1 may play a role in stabilizing angiogenic vessels and contribute to resistance to anti-VEGF therapies. Given our observation of its expression in the vasculature of many human tumor types and in circulating ECs from patients with advanced cancers, ALK1 blockade may represent an effective therapeutic opportunity complementary to the current antiangiogenic modalities in the clinic.

Suitable reference genes for relative quantification of miRNA expression in prostate cancer

Real time quantitative PCR (qPCR) is the method of choice for miRNA expression studies. For relative quantification of miRNAs, normalization to proper reference genes is mandatory. Currently, no validated reference genes for miRNA qPCR in prostate cancer are available. In this study, the expression of four putative reference genes (hsa-miR-16, hsa-miR-130b, RNU6-2, SNORD7) was examined with regard to their use as normalizer. After SNORD7 was already shown an inappropriate reference gene in preliminary experiments using total RNA pools, we studied the expression of the putative reference genes in tissue and normal adjacent tissue sample pairs from 76 men with untreated prostate carcinoma collected after radical prostatectomy. hsa-miR-130b and RNU6-2 showed no significantly different expression between the matched malignant and non-malignant tissue samples, whereas hsa-miR-16 was significantly underexpressed in malignant tissue. Softwares geNorm and Normfinder predicted hsa-miR-130b and the geometric mean of hsa-miR-130b and RNU6-2 as the most stable reference genes. Normalization of the four miRNAs hsa-miR-96, hsa-miR-125b, hsa-miR-205, and hsa-miR-375, which were previously shown to be regulated, shows that normalization to hsa-mir-16 can lead to biased results. We recommend using hsa-miR-130b or the geometric mean of hsa-miR-130b and small RNA RNU6-2 for normalization in miRNA expression studies of prostate cancer.

Contemporary Grading for Prostate Cancer: Implications for Patient Care

CONTEXTnThe Gleason grading system is one of the most powerful predictors of outcome in prostate cancer and a cornerstone in counseling and treating patients. Since its inception, it has undergone several modifications triggered by a change in clinical practice and a better understanding of the cancers histologic spectrum and variants and their prognostic significance.nnnOBJECTIVEnTo provide an overview of the implementation and the impact of the Gleason system as a predictive and prognostic tool in all available treatment modalities, and to compare the original and modified Gleason systems in major pathologic and clinical outcome data sets.nnnEVIDENCE ACQUISITIONnA comprehensive nonsystematic Medline search was performed using multiple Medical Subject Headings such as Gleason, modified, system, outcome, biopsy, prostatectomy, recurrence, prognosis, radiotherapy, and focal therapy, with restriction to the English language and a preference for publications within the last 10 yr. All Gleason grade-related studies in the last 3 yr were reviewed. For studies before this date, we relied on prior culling of the literature for various recent books, chapters, and original articles on this topic.nnnEVIDENCE SYNTHESISnUsing the modified grading system resulted in disease upgrading with more cancers assigned a Gleason score ≥ 7 than in the past. It also resulted in a more homogeneous Gleason score 6, which has an excellent prognosis when the disease is organ confined. The vast majority of studies using both systems showed that Gleason grading of adenocarcinomas on needle biopsies and radical prostatectomies was strongly associated with pathologic stage, status of surgical margins, metastatic disease, biochemical recurrence, and cancer-specific survival, with the modified system outperforming the original one in some large series. A description of the continuous incorporation of this parameter in the clinical decision making for treating prostate cancer using all currently used treatment modalities is presented, and the findings of studies before and after the inception of the modified grading system, if available, are compared. The proposed contemporary grading prognostic categories are 3+3, 3+4, 4+3, 8, and 9-10.nnnCONCLUSIONSnThe Gleason score is one of the most critical predictive factors of prostate cancer regardless of the therapy used. Modernization of the Gleason grading system has resulted in a more accurate grading system for radical prostatectomy (RP) but has complicated the comparison of data before and after the updating. A better prognostication with the updated Gleason grading system for patients treated with modalities other than surgery can only be postulated at this time because there are limited conflicting data on radiation and no studies on other treatment modalities. Its greatest impact is the uniformly excellent prognosis associated with Gleason score 6 in RPs.

Expression of p53, p21 and cyclin D1 in penile cancer: p53 predicts poor prognosis

Aims To evaluate the role of p53, p21 and cyclin D1 expression in patients with penile cancer (PC). Methods Paraffin-embedded tissues from PC specimens from six pathology departments were subjected to a central histopathological review performed by one pathologist. The tissue microarray technique was used for immunostaining which was evaluated by two independent pathologists and correlated with cancer-specific survival (CSS). κ-statistics were used to assess interobserver variability. Uni- and multivariable Cox proportional hazards analysis was applied to assess the independent effects of several prognostic factors on CSS over a median of 32u2005months (IQR 6–66u2005months). Results Specimens and clinical data from 110 men treated surgically for primary PC were collected. p53 staining was positive in 30 and negative in 62 specimens. κ-statistics showed substantial interobserver reproducibility of p53 staining evaluation (κ=0.73; p<0.001). The 5-year CSS rate for the entire study cohort was 74%. Five-year CSS was 84% in p53-negative and 51% in p53-positive PC patients (p=0.003). Multivariable analysis showed p53 (HR=3.20; p=0.041) and pT-stage (HR=4.29; p<0.001) as independent significant prognostic factors for CSS. Cyclin D1 and p21 expression were not correlated with survival. However, incorporating p21 into a multivariable Cox model did contribute to improved model quality for predicting CSS. Conclusions In patients with PC, the expression of p53 in the primary tumour specimen can be reproducibly assessed and is negatively associated with cancer specific survival.

p16INK4a is a Marker of Good Prognosis for Primary Invasive Penile Squamous Cell Carcinoma: A Multi-Institutional Study

PURPOSEnWe assessed the prognostic role of p16(INK4a) expression in penile cancer with respect to cancer specific survival.nnnMATERIALS AND METHODSnBased on a multi-institutional collaboration wax embedded tissues from 92 surgically treated patients, including 27 with total and 65 with partial penectomy, were retrospectively evaluated. After a central histopathological review by 1 pathologist a tissue microarray was constructed for p16(INK4a) immunostaining. Two independent pathologists evaluated p16(INK4a) expression, which was correlated with cancer specific survival. The κ statistic was used to assess interobserver variability. Univariate and multivariate Cox proportional hazards analysis was applied to assess the independent effects of prognostic factors on cancer specific survival during a median postoperative followup of 32 months (IQR 6-66).nnnRESULTSnThe κ statistic revealed excellent interobserver agreement (κ 0.934, p <0.001). Two and 5-year cancer specific survival rates for the entire study cohort were 86% and 74%, respectively. The 2 and 5-year rates for patients without and with p16(INK4a) expression differed significantly (73% and 57% vs 95% and 85%, respectively, p = 0.011). Univariate analysis revealed p16(INK4a) expression as a significant prognostic factor with respect to cancer specific survival (p = 0.018). Multivariate analysis identified koilocytosis (HR 0.24, 95% CI 0.07-0.83, p = 0.024), p16(INK4a) expression (HR 0.44, 95% CI 0.23-0.84, p = 0.013), and histological stage (HR 3.54, 95% CI 1.88-6.67, p <0.001) and grade (HR 2.47, 95% CI 1.00-6.09, p = 0.049) as independent prognostic factors for cancer specific survival.nnnCONCLUSIONSnResults show that p16(INK4a) seems to be a prognostic parameter for primary invasive penile cancer with excellent interobserver reproducibility. At pathology laboratories without antibodies against p16(INK4a) conventional histological determination of koilocytosis by the pathologist also appears to provide important prognostic information for cancer specific survival.

Gene Promoter Methylation and Its Potential Relevance in Early Prostate Cancer Diagnosis

Aims: We investigated hypermethylation of the glutathione S-transferase pi (GSTP1), retinoic acid receptor β2 (RARβ2), adenomatous polyposis coli (APC) and paired-like homeodomain transcription factor 2 (PITX2) gene promoters which could serve as a sensitive tool to indicate a risk of prostate cancer even in histologically tumor-free tissues. Methods: Tumor tissues and non-neoplastic tissues at variable distances from the tumor foci were retrieved from 25 formalin-fixed and paraffin-embedded prostatectomy specimens and subjected to DNA extraction. The methylation levels were assessed by means of different assay technologies. Results: Significantly increased methylation levels in cancer specimens were found for all promoter regions (GSTP1: 21/25, 84%; RARβ2: 24/25, 96%; APC: 21/25, 84%; PITX2: 20/25, 80%) and in most samples containing prostatic intraepithelial neoplasia. Several samples showed increased RARβ2 and APC methylation in adjacent non-neoplastic tissue. An association between the methylation extent of GSTP1, APC and RARβ2, respectively, and primary Gleason grade was detectable. GSTP1 methylation was also associated with extraprostatic tumor extension. Conclusion: GSTP1, APC, RARβ2 and PITX2 methylation occur frequently in prostate cancer, making these markers sensitive tools for the detection of neoplastic lesions in the prostate. For RARβ2, the results suggest a kind of methylation field effect which could be helpful for the detection of prostate cancer. Larger studies are necessary to investigate a potential correlation of GSTP1, RARβ2 and APC hypermethylation with tumor aggressiveness.

RECK overexpression decreases invasive potential in prostate cancer cells.

RECK is a tumor suppressor which inhibits metastasis and angiogenesis. Based on RECK expression in prostate cancer tissue and cell lines, our aim was to investigate functional relevance of RECK for prostate carcinoma.

Scoring the percentage of Ki67 positive nuclei is superior to mitotic count and the mitosis marker phosphohistone H3 (PHH3) in terms of differentiating flat lesions of the bladder mucosa

Aims To systematically compare different approaches for evaluating mucosal proliferative activity regarding their diagnostic role for delineating flat lesions of the bladder mucosa. Methods 32 carcinoma in situ (CIS) and 31 flat non-CIS conditions (low-grade dysplasia and reactive atypia) of the bladder mucosa were assessed by two independent pathologists in two rounds in terms of their proliferative activity assessed by the mitotic counts on H&E-stained sections (mitoses per mm2) and immunohistochemically using the MIB-1 antibody and the mitosis marker phosphohistone H3 (PHH3). Two different approaches for immunoscoring (percentage of stained nuclei vs dichotomised height of mucosal staining considering lower half vs full-thickness marker expression) were applied. κ statistics were used to evaluate interobserver and intraobserver reproducibility. Results Scoring the percentage of Ki67 expressing cell nuclei seems to be superior to dichotomisation of the height of mucosal staining as well as to PHH3 immunostaining and conventional mitotic counts in terms of delineating CIS from flat non-CIS conditions. This approach shows substantial (κ=0.62–0.65; p<0.001) interobserver and substantial to almost perfect (κ=0.67–0.83; p<0.001) intraobserver reproducibility. Conclusions The MIB-1 antibody is a useful adjunct in the differential diagnosis of conventionally challenging flat lesions of the bladder mucosa. In particular, 16% or more Ki67 positive cell nuclei favours CIS over flat non-CIS conditions, whereas 15% or less Ki67 positive cell nuclei is supportive of non-CIS conditions. However, due to some important limitations of MIB-1 staining, the MIB-1 antibody should be used as a component of a panel.

Different HER2 Protein Expression Profiles Aid in the Histologic Differential Diagnosis Between Urothelial Carcinoma In Situ (CIS) and Non-CIS Conditions (Dysplasia and Reactive Atypia) of the Urinary Bladder Mucosa

We evaluated HER2 expression profiles in 32 carcinoma in situ (CIS) and 31 non-CIS conditions (5 dysplasia and 26 reactive atypia) of the urinary bladder mucosa by applying breast cancer scoring rules. In situ hybridization was performed on tissue microarrays to assess HER2 gene amplification status. Our immunoprofiling data disclosed moderate to strong HER2 expression in CIS, including the basal layer of the urothelium, and absent to weak HER2 expression in non-CIS conditions. From the histologic differential diagnostic standpoint, immunostaining for HER2 protein represents a useful adjunct to aid in the delineation between CIS and non-CIS conditions of the bladder mucosa. Pathogenically, aberrant HER2 protein expression in CIS seems to be more commonly associated with polysomy than with gene amplification. From a therapeutic viewpoint, prospective clinical studies should investigate the potential benefit of HER2-targeted therapies in CIS, particularly in cases unresponsive to conventional therapeutic regimens.