Microscopic Kidney Disease in Tuberous Sclerosis Complex and Treatment With mTOR Inhibition.

Declining kidney function in tuberous sclerosis complex (TSC) is often attributed to large lesions, including angiomyolipomas (AMLs) and cysts, that encroach on the normal parenchyma or that require intervention and loss of parenchyma from surgical debulking or embolization. Consequently, research on inhibitors of the mammalian target of rapamycin (mTOR), a protein complex implicated in TSC pathophysiology for its role in promoting cell growth and proliferation, has largely focused on their ability to reduce AML size. Clinical guidelines distilled from this research limit mTOR inhibition as a first-line treatment to patients with large AMLs. However, chronic kidney disease (CKD) occurs in patients without large AMLs or a history of renal intervention. Alternate mechanisms postulated for CKD in TSC may suggest a role for mTOR inhibition in this population. In this report, we present 2 cases of a microscopic variant of TSC kidney disease causing declining kidney function, as well as anecdotal evidence for the use of mTOR inhibition to improve kidney function in the absence of large AMLs. We highlight the importance of annual kidney function assessment in patients with TSC and suggest a low threshold for kidney biopsy in patients with declining glomerular filtration rate without a clear etiology clinically or radiographically.

Informatics for practicing anatomical pathologists: marking a new era in pathology practice.

Informatics can be defined as using highly advanced technologies to improve patient diagnosis or management. Pathology informatics had evolved as a response to the overwhelming amount of information that was available, in an attempt to better use and maintain them. The most commonly used tools of informatics can be classified into digital imaging, telepathology, as well as Internet and electronic data mining. Digital imaging is the storage of anatomical pathology information, either gross pictures or microscopic slides, in an electronic format. These images can be used for education, archival, diagnosis, and consultation. Virtual microscopy is the more advanced form of digital imaging with enhanced efficiency and accessibility. Telepathology is now increasingly becoming a useful tool in anatomical pathology practice. Different types of telepathology communications are available for both diagnostic and consultation services. The spectrum of applications of informatics in the field of anatomical pathology is broad and encompasses medical education, clinical services, and pathology research. Informatics is now settling on solid ground as an important tool for pathology teaching, with digital teaching becoming the standard tool in many institutions. After a slow start, we now witness the transition of informatics from the research bench to bedside. As we are moving into a new era of extensive pathology informatics utilization, several challenges have to be addressed, including the cost of the new technology, legal issues, and resistance of pathologists. It is clear from the current evidence that pathology informatics will continue to grow and have a major role in the future of our specialty. However, it is also clear that it is not going to fully replace the human factor or the regular microscope.

Expression of immune checkpoints in active nonsegmental vitiligo: a pilot study.

BACKGROUND: Vitiligo is a depigmentary skin disfigurement resulting from destruction of melanocytes caused by a possible malfunctioning immunity. This destruction could be linked to an aberrant T-cell-mediated immune response. Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and programmed death-1 (PD-1) are immune checkpoints capable of downregulating T-cell immune functions. OBJECTIVES: To evaluate the pattern of expression of PD-1 and CTLA-4 in active vitiligo skin. METHODS: Thirty nonsegmental vitiligo (NSV) patients had been included in this pilot study. Marginal, lesional, and nonlesional skin biopsies were obtained. PD-1 and CTLA-4 immunohistochemistry expression in the mononuclear inflammatory infiltrates were evaluated using digital images. RESULTS: The marginal and lesional inflammatory infiltrates were significantly abundant when compared to nonlesional ones. The marginal infiltrates were significantly abundant when compared to the lesional ones. PD-1 and CTLA-4 were significantly expressed in the marginal and lesional infiltrates when compared to nonlesional skin. Moreover, the marginal expression of PD-1 was significantly higher than the lesional expression. However, no similar significant difference in CTLA-4 expression was found between the marginal and lesional infiltrates. Significant positive correlations were found between the expressions of PD-1 and CTLA-4 in marginal and lesional infiltrates. CONCLUSION: Programmed death-1 and CTLA-4 are expressed within the inflammatory infiltrate of active NSV. Further studies are required to confirm their significance in the development or limitation of the disease.

Malignant cylindroma of the scalp treated with staged perimeter excision: A case report and literature review.

Malignant cylindroma is a rare and poorly understood cutaneous malignancy. There is a paucity of literature on these lesions, with only a select number of case reports and limited guidelines on management. We present a case of a 60-year old patient with a malignant cylindroma of the scalp treated surgically with staged perimeter excision and summarize our review of the literature with a focus on management of this potentially aggressive disease.

An update on the molecular pathology of urinary bladder tumors.

Urothelial carcinoma is the fourth most common tumors after prostate cancer, lung, and colorectal carcinoma but the second most common urologic malignancy. Urothelial carcinoma composed more than 90% of bladder tumors while squamous cell carcinoma and adenocarcinomas composed 5% and 2% respectively. The intense research involving the different molecular aspects of bladder cancer has provided a great insight into identifying more about molecular profiling and pathways of bladder cancer. In this review, we will highlight the general concepts of the molecular features; profiling and classification as well as the molecular pathways for bladder carcinomas, especially urothelial carcinoma. Also, we will discuss the advances of molecular biomarkers for screening, early diagnosis, surveillance and potential prognosis of urothelial carcinoma of the bladder. Studies showed that accumulation of genetic alterations involving the clonal expansion of altered cells with growth advantages through sequential multi-step pathways results in progression of bladder tumors. The accumulated research data from literature has revealed that the genomic signatures of urothelial carcinoma are required to subclassify bladder cancer into genetically distinct subgroups. These findings could improve the understating of pathogenesis as well as will provide new therapeutic modules e.g. targeted therapy.

Incidental Prostate Adenocarcinoma in Cystoprostatectomy Specimens: Partial Versus Complete Prostate Sampling.

BACKGROUND: The rate of incidental prostate adenocarcinoma (PCa) detection in radical cystoprostatectomy (RCP) varies widely, ranging from 15% to 54%. Such variability may be explained by institutional differences in prostate grossing protocols. Either partial or complete submission of the prostate gland in RCP may result in detection of clinically insignificant or significant incidental PCa. The aim of the study was to compare the clinical significance of PCa in RCP specimens in partial versus complete sampling. MATERIAL: Seventy-two out of 158 RCP cases showed incidental PCa. The pathologic features, including Gleason score, margin status, extraprostatic extension (EPE), seminal vesicle invasion (SVI), PCa stage, and tumor volume, were assessed. RESULTS: The 72 cases were divided into partial (n = 21, 29.1%) and complete sampling (n = 51, 70.8%) groups. EPE was detected in 13/72 (18.1%) with 11/13 (84.6%) cases in the complete group. Positive margins were present in 11/72 (15.3%) with 9/11 (81.8%) in the complete group. SVI was detected in 4/72 (5.6%) with 3/4 (75.0%) in the complete group. Overall, 4/72 (5.6%) had a Gleason score >7, all of which were in the complete group. CONCLUSION: Our data suggest that complete sampling of the prostate may be the ideal approach to grossing RCP specimens, allowing for greater detection of clinically significant incidental PCa.

Knockin of SV40 Tag oncogene in a mouse adenocarcinoma of the prostate model demonstrates advantageous features over the transgenic model.

Prostate cancer (CaP) is the most common cancer in adult men in North America. Since there is no naturally occurring prostate cancer in the mouse, preclinical studies stipulate for the establishment of a genetically manipulated mouse CaP model with features close to the human situation. In view of the limitations of transgenic technique-derived CaP models, herein we report the first application of knockin technology to establish a new mouse adenocarcinoma prostate model (PSP-KIMAP) by targeting of SV40 Tag to a prostate tissue-specific gene, PSP94 (prostate secretory protein of 94 amino acids). In order to demonstrate its novelty, we compared KIMAP to a PSP94 gene-directed transgenic mouse adenocarcinoma of the prostate (PSP-TGMAP) model. The CaP development of the PSP-KIMAP mice started almost immediately after puberty at 10 weeks of age from mouse prostatic intraepithelial neoplasia (mPIN) with microinvasion to well-differentiated CaP, and demonstrated a close-to-human kinetics of prolonged tumor growth and a predominance of well and moderately differentiated tumors. The invasive nature of KIMAP model was demonstrated by multitissue metastases (lymph node, lung and liver etc) and also by immunohistochemical study of multiple invasive prostate tumor markers. PSP-KIMAP model is responsive to androgen deprivation (castration). The knockin technology in our KIMAP model demonstrates highly predictive CaP development procedures and many advantageous features, which the traditional transgenic technique-derived CaP models could not reach for both basic and clinical studies. These features include the high stability of both phenotype and genotype, highly synchronous prostate cancer development, high and precise prostate tissue targeting and with no founder line variation. The differences between the two CaP models were attributed to the introduction of a single endogenous knockin mutation, resulting in a CaP model self-regulated and controlled by a prostate gene promoter/enhancer of PSP94.

Hypoxia-induced, perinecrotic expression of endothelial Per-ARNT-Sim domain protein-1/hypoxia-inducible factor-2alpha correlates with tumor progression, vascularization, and focal macrophage infiltration in bladder cancer.

Endothelial Per-ARNT-Sim (PAS) domain protein-1 (EPAS-1)/hypoxia-inducible factor-2alpha (HIF-2alpha) is a member of the basic helix-loop-helix/PAS domain protein family and is considered to be an endothelial-specific, hypoxia-inducible transcription factor. Because hypoxia is a fundamental element of tumor biology determining clinical outcome, we performed an immunohistochemical study of EPAS-1 expression in a cohort of bladder cancer cases and assessed the possible correlation of EPAS-1 expression with tumor hypoxia and growth. In the 67 cases (37 radical cystectomy and 30 transurethral resection) studied, overexpression of EPAS-1/HIF-2alpha protein was not found in cancer cells or in normal tissues but was mostly found in stroma around cancer cells, and strong positive staining was noted in perinecrotic regions. The perinecrotic/tumorous expression of EPAS-1/HIF-2alpha was correlated statistically with higher histological grade (P < 0.001), advanced pathological T stage (P < 0.001), and presence of necrosis (P < 0.001). A parallel immunohistochemical analysis of a marker gene of vascular endothelial growth factor demonstrated its positive correlation with tumor grade, stage, and EPAS-1/HIF-2alpha overexpression, supporting the correlation of EPAS-1/HIF-2alpha up-regulation with tumor angiogenesis. To further clarify the relationship between hypoxia and vascularity in the perinecrotic/tumorous area with EPAS-1/HIF-2alpha expression, tissue microvessel density (MVD) was assessed. No significant correlation (P = 0.442) was found between EPAS-1/HIF-2alpha expression and MVD if the 67 tumors of different stages were all included. However, EPAS-1/HIF-2alpha-positive cases had lower MVD than EPAS-1/HIF-2alpha-negative cases (P = 0.001) if only invasive cancer cases were analyzed. In addition, in all EPAS-1/HIF-2alpha-positive staining cases, EPAS-1/HIF-2alpha-positive foci had lower MVD than EPAS-1/HIF-2alpha-negative foci (P < 0.001). Finally, using serial sections, the location of EPAS-1/HIF 2alpha expression was identified mainly in tumor-associated macrophage (TAM) as well as in some fibroblast cells. Focal TAM infiltration was identified at a higher level in EPAS-1-positive cases than EPAS-1-negative cases (P < 0.001). This is the first clinical report suggesting that hypoxia-induced, perinecrotic EPAS-1/HIF-2alpha expression is correlated with tumor progression and angiogenesis at higher grade and stage through focal TAM infiltration in invasive bladder cancer.

Incidental Merkel cell carcinoma in a cutaneous horn: a case report.

Merkel cell carcinoma (MCC) is a rare cutaneous neuroendocrine malignancy, which usually presents as an asymptomatic, rapidly growing, firm nodule on sun-damaged skin. We present a 93-year-old female who presented with a "cutaneous horn" on the face. On excision, histologic examination revealed a combined squamous cell carcinoma in situ with underlying MCC. Merkel cell polyomavirus immunohistochemistry was negative in this lesion. This case report highlights the significant association between MCC and squamous cell carcinoma and the uncommon clinical presentation of this combined tumor in the form of a cutaneous horn.

Profilin-1 expression is associated with high grade and stage and decreased disease-free survival in renal cell carcinoma.

Clear cell renal cell carcinoma (ccRCC) is associated with high mortality, although individual outcomes are highly variable. Identification of patients with increased risk of disease progression can guide customizing management plan according to disease severity. Profilin-1 (Pfn1) has been recently identified as overexpressed in metastatic ccRCC compared with primary tumors. We examined Pfn1 expression in a tissue microarray of 384 cases of histologically confirmed primary ccRCC with detailed clinical follow-up. Profilin-1 expression showed both cytoplasmic and nuclear staining patterns. The immunoexpression of Pfn1 was scored in a semiquantitative fashion. There was no significant difference in Pfn1 expression between normal kidney and kidney ccRCC. Our results show that strong cytoplasmic Pfn1 expression is associated with high-grade (P < .001) and high-stage (III-IV) (P = .018) disease. Univariate analysis of the data set showed that higher Pfn1 expression is associated with significantly shorter disease-free survival (hazard ratio 7.36, P = .047) and also lower overall survival. Kaplan-Meier analysis showed that high cytoplasmic expression of Pfn1 was also associated with a statistically significant lower disease-free survival (P = .018). It was also associated with lower overall survival, although this was not statistically significant. Profilin-1 lost its prognostic significance in the multivariate analysis when controlling for grade and stage. Profilin-1 expression was not associated with significant prognostic deference in the subgroup of patients with stage 1 disease. Our results suggest that the evaluation of Pfn1 by immunohistochemistry may help to identify patients with an increased risk of disease progression. We validated our results at the messenger RNA level on an independent patient cohort. Higher messenger RNA expression of Pfn1 is associated with significantly lower survival.

A rare case of recurrent urinary obstruction and acute renal failure from cystitis cystica et glandularis.

We report a rare case of recurrent florid cystitis cystica et glandularis (CCEG), common type, causing obstruction of the left ureterovesicle junction (UVJ) leading to renal colic and hydronephrosis. A 43-year-old man was admitted with renal colic, left UVJ obstruction, left hydronephrosis and azotemia. Cystoscopy showed a >4-cm bladder lesion compressing the left UVJ. Transurethral resection of the bladder tumour (TURBT) was performed and pathology revealed the lesion as CCEG. Two months later, the CCEG recurred and caused left UVJ obstruction a second time, requiring TURBT.

Evaluation and prognostic significance of human tissue kallikrein-related peptidase 6 (KLK6) in colorectal cancer.

The prognosis of patients with colorectal cancer (CRC) is assessed through conventional clinicopathological parameters, which are not always accurate. Members of the human kallikrein-related peptidases gene family represent potential cancer biomarkers. The aim of this study was to investigate the expression of human tissue kallikrein-related peptidase 6 (KLK6) by immunohistochemistry in CRC to correlate this expression with various histopathological and clinical variables, and to evaluate its significance as a predictor of disease outcome. KLK6 expression was evaluated by immunohistochemistry and an expression score was calculated for each case. In CRC, KLK6 expression was decreased compared to normal colonic mucosa. A statistically significant, positive association was observed between KLK6 and tumor stage (p=0.036), lymph node metastases (p=0.030), and liver metastases (p=0.025). Univariate analysis showed that KLK6 expression and stage had statistically significant correlation with disease-free survival (p=0.045 and p<0.001, respectively) and overall survival (p=0.027 and p<0.001, respectively). Cox multivariate analysis showed that KLK6 expression was an independent predictor of unfavorable overall survival (p=0.041). Kaplan-Meier survival curves showed that KLK6-positive patients have statistically significant lower disease-free and overall survival. In conclusion, KLK6 immunostaining is an independent prognostic marker in patients with CRC.

Invasive lobular carcinoma of the breast presenting as retroperitoneal fibrosis: a case report.

INTRODUCTION: Invasive lobular carcinoma of the breast represents approximately 6.3% of mammary malignancies. Distant metastasis of invasive lobular carcinoma to the peritoneum or retroperitoneum has been reported fairly frequently. CASE PRESENTATION: We report the case of a 59-year-old Caucasian-Canadian woman with invasive lobular carcinoma of the breast presenting with retroperitoneal fibrosis and bilateral ureteral obstruction. Intra-operative pathology consultation did not reveal malignancy. The diagnosis, however, was confirmed on permanent sections by histological appearance in addition to immunohistochemistry. To the best of our knowledge, this is the first reported case of invasive lobular carcinoma of the breast presenting with retroperitoneal fibrosis. CONCLUSION: In a case of unexplained ureteric obstruction and retroperitoneal fibrosis, more comprehensive physical examination and additional ancillary studies may be warranted to rule out malignancy as an underlying etiology. This case also emphasizes that intra-operative frozen section consultation cannot always be fully relied upon to exclude a malignancy as the etiology of retroperitoneal fibrosis. Moreover, in permanent histopathology sections, immunohistochemistry testing can be of value to rule out metastatic disease where the morphology is not salient. There is a need for a thorough physical examination of patients with retroperitoneal fibrosis, including the breast and gynecological organs.

A novel knock-in prostate cancer model demonstrates biology similar to that of human prostate cancer and suitable for preclinical studies.

Preclinical studies of prostate cancer (CaP) have employed a genetically engineered mouse model, since there is no naturally occurring CaP in rodents. We have previously reported a new knock-in mouse adenocarcinoma prostate (KIMAP) model. In this study, we demonstrate that the new model possesses a tumor architecture of heterogeneity and multifocality similar to that of human CaP, by utilizing a new compound scoring system to compare with the PSP94 (approved gene symbol Msmb) gene-directed transgenic mouse CaP model (TGMAP). KIMAP mice showed a balanced distribution of tumor extent, which penetrated the prostate gland. Comparative studies on cDNA microarrays demonstrated that KIMAP tumors were upregulated with higher contents of immunoresponse genes, whereas PSP-TGMAP tumors had neuroendocrine (NE) differentiation. The majority of KIMAP mice did not progress to NE CaP, which was observed only at a very late stage and a low frequency. Several tumor marker genes characteristic of human CaP were uniquely identified in KIMAP tumors, including hepsin, maspin, Nkx3.1, CD10 and PSP94 (similar to PSA), etc. The differences between these two CaP models are attributed to the introduction of a single endogenous knock-in mutation. Due to the similarities between human CaP tumors and the PSP-KIMAP tumors, this preclinical model may supplement the current transgenic models to study CaP more accurately.

Mouse PSP94 expression is prostate tissue-specific as demonstrated by a comparison of multiple antibodies against recombinant proteins.

Prostate tissue-specific gene expression is crucial for driving potentially therapeutic genes to target specifically to the prostate. Prostate secretory protein of 94 amino acids (PSP94), also known as beta-MSP (microseminoprotein), is one of the three most abundant secretory proteins of the prostate gland, and is generally considered to be prostate tissue-specific. We have previously demonstrated that the expression of the rat PSP94 gene is strictly prostate tissue-specific by an antibody against a recombinant rat PSP94. In order to study prostate targeting utilizing the PSP94 gene in a mouse pre-clinical experimental model, we need to establish antibodies against mouse PSP94 to confirm if it is prostate tissue-specific as well. In this study, firstly we raised a polyclonal antibody against a recombinant glutathione-S-transferase- (GST-) mouse mature form of PSP94. However, it showed very poor immunoreactivity against prostate tissue PSP94 as tested in Western blotting experiments. Neither antibodies against rat PSP94 nor mouse PSP94 showed significant cross-reactivity. Thus a second antibody was established against a recombinant mouse mature PSP94 containing N-terminal polyhistidines, and stronger immunoreactivity against mouse prostate tissue PSP94 was identified in Western blotting experiments. Both of these antibodies showed immunohistochemical reactivity, while the latter showed stronger reactivity in IHC when tested with different fixatives. By studying tissue distribution, we demonstrated that, as with rat PSP94, mouse PSP94 is strictly prostate tissue-specific in experiments of both Western blotting and immunohistochemistry (IHC). This conclusion was also derived from a comparison among antibodies against human, rat, and mouse PSP94, showing very different immunoreactivities in Western blotting and IHC. Finally, a competitive assay between different species was performed. We demonstrated that antibodies against PSP94 from different species (human, primate, rodents) have poor cross-reactivities. These observations also indicate that the PSP94 gene is a rapidly evolving gene in all species. Results from this study have led to the possibility of utilizing PSP94 as a targeting agent specifically to the prostate in a mouse experimental model.

Correlation study showing no concordance between EPAS-1/HIF-2alpha mRNA and protein expression in transitional cellcancer of the bladder.

OBJECTIVES: Endothelial Per-ARNT-Sim (PAS) domain protein-1 (EPAS-1)/hypoxia-inducible factor (HIF)-2alpha is a recently identified, endothelial-specific, hypoxia-induced transcription factor and is reputed to have an important role in tumor angiogenesis and tumor progression. Only a few studies have reported on the clinical correlation with grade, stage, necrosis, and microvessel density in transitional cell carcinoma of the bladder. In vitro studies have reported no concordance of EPAS-1/HIF-2alpha mRNA and protein expression. We sought to elucidate these two issues. METHODS: Surgical specimens from 110 patients with transitional cell carcinoma comprised the study, including 51 from radical cystectomy and 59 from transurethral resection of bladder tumor. Immunohistochemistry and in situ hybridization were performed with antibodies against EPAS-1/HIF-2alpha, CD31, and a human EPAS-1/HIF-2alpha cDNA subclone probe. RESULTS: EPAS-1/HIF-2alpha protein expression was found almost exclusively in high-grade and high-stage tumors (P <0.0001). EPAS-1/HIF-2alpha mRNA expression was detectable only in high-grade (grade 3) and high-stage (pT3a or greater) cases with positive EPAS-1/HIF-2alpha protein expression (P = 0.0017). The presence of necrosis correlated with EPAS-1/HIF-2alpha expression, tumor grade, and tumor stage (P <0.0001). Microvessel density was much lower in invasive, larger tumor nodules in EPAS-1/HIF-2alpha-positive cases than in the negative cases (P <0.0001). CONCLUSIONS: EPAS-1/HIF-2alpha protein and mRNA levels correlate with higher grade and advanced bladder transitional cell carcinoma. In lower stage cases, no concordance was found between transcription and translation of EPAS-1/HIF-2alpha gene expression. Because EPAS-1/HIF-2alpha mRNA is only detectable in highly invasive cancer cases, it may serve as a therapeutic target (eg, by an antisense mRNA approach) for bladder cancer.