Peter D. Ottosen

Snail1 is over‐expressed in prostate cancer

Transcription factor Snail1 is a mediator of cell migration and survival, and expression is elevated in several cancer types. The Snail1 gene is reportedly amplified in prostate cancer (PC), and we investigated Snail1 expression in PC. Immunohistochemical Snail1 staining was determined on a tissue microarray which includes 327 specimens of PC, 30 specimens from patients with benign prostatic hyperplasia (BPH), benign tissue from 30 PC patients and 15 high‐grade prostate intraepithelial neoplasia (high‐grade PIN) specimens. Clinicopathological and follow‐up data were available for all patients. No BPH specimen and only 21% of benign tissue from PC patients showed high expression of Snail1. Only 7% of high‐grade PIN patients expressed a high level of Snail1. In contrast, approximately 50% of PC tissue from patients with PC showed marked nuclear immunostaining. Snail1 immunostaining was significantly associated with Gleason score (p<0.05). Snail1 expression was not correlated to T stage, metastasis at time of diagnosis, risk of or time to recurrence. Snail1 expression was significantly increased in PC with a positive correlation to dedifferentiation, but not to cancer progression or prognosis. The presented data indicate that Snail1 expression is upregulated from the early stages of PC.

Genetic and Epigenetic SLC18A2 Silencing in Prostate Cancer Is an Independent Adverse Predictor of Biochemical Recurrence after Radical Prostatectomy

Purpose: This study investigates SLC18A2 (vesicular monoamine transporter 2) expression in prostate adenocarcinoma and examines its potential as a predictive marker for prostate cancer patient outcome after radical prostatectomy. Experimental Design: Expression and single nucleotide polymorphism microarray analyses identified SLC18A2 as both down-regulated and subject to common loss-of-heterozygosity in prostate cancer. Down-regulated SLC18A2 expression was validated on tissue microarrays containing benign and malignant prostate specimens from an independent patient group (n = 738). Furthermore, SLC18A2 immunoreactivity in radical prostatectomy tumor specimens (n = 506) was correlated to clinicopathologic characteristics and recurrence-free survival. The possibility of SLC18A2 silencing by aberrant DNA methylation in prostate cancer cells was investigated by bisulfite sequencing. Results: Tissue microarray analysis revealed markedly lower cytoplasmic SLC18A2 staining in cancer compared with nonmalignant prostate tissue samples, confirming RNA expression profiling results. Furthermore, multivariate analysis identified cytoplasmic SLC18A2 immunoreactivity as a novel predictor of biochemical recurrence following prostatectomy (hazard ratio, 0.485; 95% confidence interval, 0.333-0.709; P < 0.001) independent of prostate-specific antigen, Gleason score, tumor stage, and surgical margin status. SLC18A2 showed loss-of-heterozygosity in 23% of the tumors and was densely hypermethylated in 15 of 17 (88%) prostate cancer samples plus 6 of 6 prostate cancer cell lines. In contrast, SLC18A2 was unmethylated in 4 of 4 adjacent nonmalignant prostate and 3 of 5 benign prostatic hyperplasia tissue samples, whereas 2 of 5 benign prostatic hyperplasia samples had monoallelic hypermethylation. Methylation and histone deacetylase inhibitory agents rescued SLC18A2 expression in three prostate cancer cell lines. Conclusions:SLC18A2 silencing by DNA hypermethylation and/or allelic loss is a frequent event in prostate cancer and a novel independent predictor of biochemical recurrence after prostatectomy.

Comparative analysis of three- and two-antibody cocktails to AMACR and basal cell markers for the immunohistochemical diagnosis of prostate carcinoma

BackgroundImmunohistochemistry using antibody cocktails against basal cell specific and cancer-associated markers is important in the diagnosis of prostate carcinoma in needle biopsies. We compared the usefulness for detecting prostate carcinoma of a three-marker cocktail of antibodies to α-methylacyl-CoA racemase (AMACR), p63 and cytokeratin (CK) 5 with a traditional two-marker cocktail of AMACR and p63.MethodsSixty-six prostate needle biopsies were analysed prospectively. Serial sections were immunostained with the two- and three- antibody cocktails. Blinded slides were assessed individually by two pathologists and sensitivity, specificity and kappa statistics were calculated.ResultsBoth antibody cocktails contributed to the detection of prostate carcinoma in needle biopsies. There was an acceptable level of agreement between the pathologists for both the cocktails. Sensitivity was similar for one pathologist comparing both the cocktails (76.4% and 75.7%), but was slightly lower comparing the three-antibody with the two-antibody cocktail for the other pathologist (66.6% vs. 77.4%, respectively). Higher specificity values of 90.3% were achieved by both pathologists using three-antibody as compared with two-antibody cocktails (68.7% and 71.8%).ConclusionsAntibody cocktails are important in diagnosing prostate carcinoma in needle biopsies. Adding an extra basal cell marker to the traditional two-antibody cocktail improves the specificity of detecting prostate carcinoma in limited needle biopsy material, and should be considered for routine diagnostic use.Virtual slidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2492231327330327

The number and size of glomeruli in long‐term lithium‐induced nephropathy in rats

Chronic renal failure was induced in 10 Wistar rats using a lithium‐containing (40 mmol/kg) diet from time of birth until an age of 55–65 weeks. Nine Wistar rats served as controls. The plasma lithium, the plasma urea, and the inulin clearance were measured, and one kidney was fixed by vascular perfusion with glutaraldehyde. The number of glomeruli was estimated stereologically by the fractionator method. The total number of glomeruli per kidney was 23.9 × 103±3.65 × 103 (±SD) in controls and 22.0 × 103±1.48 × 103 in the lithium‐treated group, showing no statistically significant difference. The mean glomerular volume was also estimated using stereological methods. The number‐weighted mean volume was reduced by 42% in the lithium‐treated group, whereas the volume‐weighted mean volume was unchanged. This can be attributed to the occurrence of many small glomeruli and a few very large glomeruli in the lithium‐treated group. The many small glomeruli have in a previous study been shown to be atubular. The present study showed that the glomerular population is quite resistant to the deleterious effect of lithium; thus glomerular atrophy was seen, but no loss of glomeruli occurred.

Downregulation of zinc finger protein 132 in prostate cancer is associated with aberrant promoter hypermethylation and poor prognosis

This study investigates the expression and biomarker potential of zinc finger protein 132 (ZNF132) in prostate cancer (PC) by transcriptional profiling and immunohistochemical analysis of tissue microarrays, including tumor specimens from 615 radical prostatectomy (RP) patients and 199 conservatively treated patients. Primary clinical endpoints were time to PSA recurrence and cancer‐specific death, respectively. Compared to normal prostate epithelial cells from men without PC, ZNF132 transcript levels were significantly reduced in PC cells from patients with localized PC and further downregulated in metastatic PC. Likewise, ZNF132 protein expression was significantly lower in primary tumors from patients with metastatic compared to localized PC and further reduced in castrate‐refractory PC, indicating that ZNF132 downregulation correlates with disease progression. Reduced ZNF132 immunoreactivity was significantly associated with high Gleason score and advanced T stage in both PC patient cohorts. By univariate analysis, no/weak ZNF132 staining was a significant adverse predictor of PSA recurrence after RP (p = 0.024) and cancer‐specific death following conservative treatment (p = 0.009). In multivariate models, however, ZNF132 did not add significant independent value to established prognostic factors. Finally, bisulfite sequencing revealed frequent promoter hypermethylation of ZNF132 in both PC cell lines and PC tissue samples, indicating that ZNF132 is epigenetically silenced in PC. In summary, our results show that downregulation of ZNF132 is associated with aggressive PC and furthermore identify ZNF132 as a new candidate methylation marker for PC.

Cellular localization of PNA binding in colorectal adenomas: Comparison with differentiation, nuclear:cell height ratio and effect of desialylation

The lectin Arachis Hypogaea (Peanut Agglutinin, PNA) was used to study the cellular localization of the Thomsen‐Friedenreich (T) disaccharide Gal‐β (1–3)‐GalNAcαI‐R in 22 formalin‐fixed paraplast‐embedded colorectal adenomas of varying cellular dysplasia. An indirect immunoperoxidase method was used prior to and after neuraminidase treatment. Detailed information on the cellular localization of PNA binding was obtained. In addition, morphometric measurements of the nuclear: cell height ratios were performed on staining‐filtered micrographs of crypts from all adenomas. We found 1) a statistically significant increase in the nuclear:cell height ratio with increasing grade of dedifferentiation (p<0.003), 2) a statistically significant smaller nuclear:cell height ratio in crypts that were PNA‐positive in the Golgi region when these were compared to crypts that were PNA‐positive on luminal cell membranes, 3) a decreasing number of crypts expressing PNA binding sites in the Golgi region with increasing dedifferentiation, leading to complete absence of PNA binding sites in Grade IV adenomas, 4) neuraminidase pretreatment increased the number of crypts expressing PNA binding sites in cytoplasm and on luminal membranes, whereas no changes were detected in crypts expressing PNA binding sites in the Golgi region. Our results confirm the general concept of accumulation of precursors of carbohydrate antigens in dedifferentiated cells. On the basis of the results presented, we conclude that the nuclear:cell height ratio shows a good correlation with the cellular localization of PNA binding, cellular differentiation and classic pathologic grading.

Smarcc1 expression: A significant predictor of disease-specific survival in patients with clinically localized prostate cancer treated with no intention to cure

Abstract Objective. The clinical outcome of prostate cancer (PC) is extremely variable and therefore difficult to predict at the early stage of the disease. Since curative-intended therapies are bound up with the risk of severe adverse events, identification of new prognostic markers in PC is essential in individualized clinical treatment. The Smarcc1 protein, a part of the intranuclear SWI/SNF complex, is up-regulated in PC, and has been suggested to be implicated in tumour dedifferentiation, progression and biochemical recurrence. This makes Smarcc1 a possible candidate marker for PC survival. Material and methods. Immunohistochemistry was used to measure protein expression levels of Smarcc1in on a tissue microarray containing specimens from 100 patients suffering from clinically localized PC treated with no intention to cure and followed to death. Results. The median age at diagnosis was 75.5 years (55–95 years) and the median survival time was 5 years (0.01–15 years). In total, 41 patients (41%) died of PC. Statistically, there was no significant association between Smarcc1 immunostaining (negative/positive) and Gleason score (p = 0.7/0.8) or the clinical T stage (p = 0.9). Positive staining for Smarcc1 in patients with clinically localized PC correlated with a prolonged disease-free survival as opposed to negative staining (p = 0.025). Conclusion. In patients with clinically localized PC treated without intention of cure, Smarcc1 expression was a statistically significant and independent predictor of disease-specific survival.