In Vivo and Ex Vivo Microscopy: Moving Toward the Integration of Optical Imaging Technologies Into Pathology Practice.

The traditional surgical pathology assessment requires tissue to be removed from the patient, then processed, sectioned, stained, and interpreted by a pathologist using a light microscope. Today, an array of alternate optical imaging technologies allow tissue to be viewed at high resolution, in real time, without the need for processing, fixation, freezing, or staining. Optical imaging can be done in living patients without tissue removal, termed in vivo microscopy, or also in freshly excised tissue, termed ex vivo microscopy. Both in vivo and ex vivo microscopy have tremendous potential for clinical impact in a wide variety of applications. However, in order for these technologies to enter mainstream clinical care, an expert will be required to assess and interpret the imaging data. The optical images generated from these imaging techniques are often similar to the light microscopic images that pathologists already have expertise in interpreting. Other clinical specialists do not have this same expertise in microscopy, therefore, pathologists are a logical choice to step into the developing role of microscopic imaging expert. Here, we review the emerging technologies of in vivo and ex vivo microscopy in terms of the technical aspects and potential clinical applications. We also discuss why pathologists are essential to the successful clinical adoption of such technologies and the educational resources available to help them step into this emerging role.

In Vivo and Ex Vivo Microscopy: A Business Plan to Justify the Introduction of Similar Emerging Technologies Into Pathology Practice.

CONTEXT.­: Our patients are now demanding value for their medical diagnoses and treatment in terms of optimal costs, quality, and outcomes. The financial justification for the introduction of new emerging technologies that may better meet these needs will depend on many factors, even if there is an established reimbursement code. In vivo and ex vivo microscopic technologies (IVM and EVM, respectively) will be used as examples of potentially transforming technologies. OBJECTIVE.­: To describe the components of a business plan that ensures all of the ramifications of introducing a new technology into pathology practice have been considered. As well as the financial justification, such a plan should include strategic vision and congruence, the advantages and drawbacks of introducing such technology, and how plans for marketing, implementation, and verification can be operationalized. DATA SOURCES.­: Unlike many pathologists, administrative directors in clinical laboratories already know the components of a financially sound business plan. In addition to the financial justifications, other considerations of such a plan include expense reductions, multiyear buildups in revenue generation, the replacement of other technologies, improved productivity and workflows, additional space, new capital, retrained personnel, and the impact on other departments. CONCLUSIONS.­: Pathologists will learn a business plan format to improve their confidence in making the sound financial justifications needed to consider the introduction of an emerging technology into pathology practice, even when there is initially no obvious revenue stream because formal reimbursement codes have not been established.

Amelioration of Diabetic Nephropathy Using a Retinoic Acid Receptor ß2 Agonist.

Vitamin A (VA) and its derivatives, known as retinoids, play critical roles in renal development through retinoic acid receptor ß2 (RARß2). Disruptions in VA signaling pathways are associated with the onset of diabetic nephropathy (DN). Despite the known role of RARß2 in renal development, the effects of selective agonists for RARß2 in a high-fat diet (HFD) model of DN are unknown. Here we examined whether AC261066 (AC261), a highly selective agonist for RARß2, exhibited therapeutic effects in a HFD model of DN in C57BL/6 mice. Twelve weeks of AC261 administration to HFD-fed mice was well tolerated with no observable side effects. Compared with HFD-fed mice, HFD + AC261-treated mice had improved glycemic control and reductions in proteinuria and urine albumin-to-creatinine ratio. Several cellular hallmarks of DN were mitigated in HFD + AC261-treated mice, including reductions in tubule lipid droplets, podocyte (POD) effacement, endothelial cell collapse, mesangial expansion, and glomerular basement membrane thickening. Mesangial and tubule interstitial expression of the myofibroblast markers α-smooth muscle actin (α-SMA) and type IV collagen (Col-IV) was lower in HFD + AC261-treated mice compared with HFD alone. Ultrastructural and immunohistochemistry analyses showed that, compared with HFD-fed mice, HFD + AC261-treated mice showed preservation of POD foot process and slit-diaphragm morphology, an increase in the levels of slit-diagram protein podocin, and the transcription factor Wilms tumor-suppressor gene 1 in PODs. Given the need for novel DN therapies, our results warrant further studies of the therapeutic properties of AC261 in DN.

Role of NADH Dehydrogenase (Ubiquinone) 1 Alpha Subcomplex 4-Like 2 in Clear Cell Renal Cell Carcinoma.

PURPOSE: We delineated the functions of the hypoxia-inducible factor-1α (HIF1α) target NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 4-like 2 (NDUFA4L2) in clear cell renal cell carcinoma (ccRCC) and characterized NDUFA4L2 as a novel molecular target for ccRCC treatment. EXPERIMENTAL DESIGN: We evaluated normal kidney and ccRCC patient microarray and RNAseq data from Oncomine and The Cancer Genome Atlas for NDUFA4L2 mRNA levels and the clinical implications of high NDUFA4L2 expression. In addition, we examined normal kidney and ccRCC patient tissue samples, human ccRCC cell lines, and murine models of ccRCC for NDUFA4L2 mRNA and protein expression. Utilizing short hairpin RNA, we performed NDUFA4L2 knockdown experiments and analyzed the proliferation, clonogenicity, metabolite levels, cell structure, and autophagy in ccRCC cell lines in culture. RESULTS: We found that NDUFA4L2 mRNA and protein are highly expressed in ccRCC samples but undetectable in normal kidney tissue samples, and that NDUFA4L2 mRNA expression correlates with tumor stage and lower overall survival. In addition, we demonstrated that NDUFA4L2 is an HIF1α target in ccRCC and that NDUFA4L2 knockdown has a profound antiproliferative effect, alters metabolic pathways, and causes major stress in cultured RCC cells. CONCLUSIONS: Collectively, our data show that NDUFA4L2 is a novel molecular target for ccRCC treatment. Clin Cancer Res; 22(11); 2791-801. ©2016 AACR.

Multiphoton microscopy for rapid histopathological evaluation of kidney tumours.

OBJECTIVE: To explore the potential of multiphoton microscopy (MPM) for rapid evaluation and triaging of ex vivo kidney tissue. MATERIALS AND METHODS: Fresh neoplastic and non-neoplastic tissues from nephrectomy specimens (n = 40) were imaged with MPM and later submitted for routine histopathology. RESULTS: On MPM, normal kidney architecture was evident and clearly distinguishable from tumour. Forty malignant tumours (20 clear-cell renal cell carcinomas [RCCs], 10 papillary RCCs, five chromophobe RCCs and five papillary urothelial carcinomas [UCs], as diagnosed by haematoxylin and eosin staining) were imaged and subtyped as non-papillary and papillary, based on their architecture. Non-papillary tumours were further classified based on their unique cytoplasmic signatures. Clear-cell RCCs had a predominant population of cells with fat droplets in cytoplasm. Chromophobe RCCs had cells with non-fatty/homogeneous cytoplasm and distinct intra-cytoplasmic granules. Papillary RCCs had single-cell-lined papillae with often abundant histiocytes in their core, whereas PUC had multi-layered urothelium-lined papillae. The diagnostic accuracy of tumour subtyping by two independent uropathologists was 95%. CONCLUSIONS: We showed that MPM can reliably differentiate neoplastic from non-neoplastic kidney tissue and subtype kidney tumours in fresh, unprocessed tissue, MPM might therefore be useful as a rapid real-time diagnostic tool for the evaluation of kidney biopsies, and surgical margins in partial nephrectomies, to improve overall patient management.

Multiphoton microscopy: a potential intraoperative tool for the detection of carcinoma in situ in human bladder.

CONTEXT: Urothelial carcinoma in situ (CIS) is a precursor of invasive bladder cancer, which if left untreated, will likely progress to more aggressive disease. Approximately 50% of CIS lesions are missed on routine cystoscopy owing to their flat architecture. Furthermore, many benign but abnormal-appearing areas may be biopsied owing to lack of cellular resolution of cystoscopes. Multiphoton microscopy (MPM) is an optical imaging technique that generates subcellular-resolution three-dimensional images from unfixed tissue without using exogenous dyes. OBJECTIVE: To assess the diagnostic potential of MPM in identifying and differentiating benign from malignant flat bladder lesions, especially CIS. DESIGN: Seventy-eight specimens (benign = 46, CIS = 23, invasive = 9, as diagnosed on histopathology) were obtained from flat bladder mucosa via transurethral resection of bladder, cold cup biopsy, or cystectomy, imaged fresh with a commercial benchtop MPM, and submitted for routine histopathology. Multiphoton microscopy and hematoxylin-eosin diagnoses were compared. RESULTS: In 77 of 78 specimens (99%), accurate MPM diagnoses (benign/malignant) were given on the basis of their architectural and cytologic features (nuclear to cytoplasmic ratio, pleomorphism, polarity/organization of urothelial layers, etc). The sensitivity and specificity were 97% and 100%, respectively, with positive (malignant) and negative (benign) predictive values of 100% and 98%, respectively. The interobserver agreement, κ, was 0.93. CONCLUSIONS: Our study demonstrates the capability of MPM to identify and differentiate benign from malignant flat bladder lesions, especially CIS. With the advent of MPM endoscopes, we foresee their potential as a biopsy guidance tool for early detection and treatment of CIS, thus reducing the rate of biopsies with benign diagnoses and their associated complications.

Multiphoton gradient index endoscopy for evaluation of diseased human prostatic tissue ex vivo.

Multiphoton microscopy can instantly visualize cellular details in unstained tissues. Multiphoton probes with clinical potential have been developed. This study evaluates the suitability of multiphoton gradient index (GRIN) endoscopy as a diagnostic tool for prostatic tissue. A portable and compact multiphoton endoscope based on a 1-mm diameter, 8-cm length GRIN lens system probe was used. Fresh ex vivo samples were obtained from 14 radical prostatectomy patients and benign and malignant areas were imaged and correlated with subsequent H&E sections. Multiphoton GRIN endoscopy images of unfixed and unprocessed prostate tissue at a subcellular resolution are presented. We note several differences and identifying features of benign versus low-grade versus high-grade tumors and are able to identify periprostatic tissues such as adipocytes, periprostatic nerves, and blood vessels. Multiphoton GRIN endoscopy can be used to identify both benign and malignant lesions in ex vivo human prostate tissue and may be a valuable diagnostic tool for real-time visualization of suspicious areas of the prostate.

Prostate cancer with Paneth cell-like neuroendocrine differentiation has recognizable histomorphology and harbors AURKA gene amplification.

Aurora kinase A (AURKA) gene amplification has been documented in 67% of hormone-naive prostate cancer cases that progress to a highly aggressive variant of castrate-resistant disease, clinically referred to as "neuroendocrine" prostate cancer, "small cell" prostate carcinoma, or "anaplastic" prostate cancer. Therefore, AURKA amplification is a potential prognostic biomarker that may help to identify patients with prostate cancer who are at high risk for developing castrate-resistant disease with clinical features of small cell carcinoma. Furthermore, AURKA inhibitors are currently being tested in clinical trials. In a previous study, we found AURKA amplification in 6 cases of prostate cancer with Paneth cell-like cells. This morphologic pattern has been suggested to represent low-grade neuroendocrine differentiation (NED) with generally favorable prognosis. We sought to investigate the frequency of AURKA amplification and the histologic characteristics of prostate cancer with Paneth cell-like NED. Twenty-five cases from 172 prostatectomies were evaluated for the presence of 18 morphologic features and AURKA amplification. Most prostate cancers with Paneth cell-like NED had macronucleoli (92%), basophilic appearance (88%), perineural invasion (72%), and nuclear stratification (76%). The frequency of AURKA amplification was 45%, present throughout the examined tumor nodule including areas without Paneth cell-like cells. When histologically similar cases with and without AURKA amplification were compared, this gene alteration was associated with larger extent of Paneth cell-like NED identified at magnification ×20 (P = .015), higher percentage of Paneth cell-like NED throughout the tumor nodule (P = .033), ductal features (P = .02), and higher overall Gleason grade (P = .039). AURKA amplification was not associated with age, serum prostate specific antigen, or tumor stage. The high frequency of AURKA amplification (45%) in localized prostate cancer with Paneth cell-like NED and its potential prognostic significance warrant further investigation.

Multiphoton microscopy: a potential "optical biopsy" tool for real-time evaluation of lung tumors without the need for exogenous contrast agents.

CONTEXT: Multiphoton microscopy (MPM) is an emerging, nonlinear, optical-biopsy technique, which can generate subcellular-resolution images from unprocessed and unstained tissue in real time. OBJECTIVE: To assess the potential of MPM for lung tumor diagnosis. DESIGN: Fresh sections from tumor and adjacent nonneoplastic lung were imaged with MPM and then compared with corresponding hematoxylin-eosin slides. RESULTS: Alveoli, bronchi, blood vessels, pleura, smokers' macrophages, and lymphocytes were readily identified with MPM in nonneoplastic tissue. Atypical adenomatous hyperplasia (a preinvasive lesion) was identified in tissue adjacent to the tumor in one case. Of the 25 tumor specimens used for blinded pathologic diagnosis, 23 were diagnosable with MPM. Of these 23 cases, all but one adenocarcinoma (15 of 16; 94%) was correctly diagnosed on MPM, along with their histologic patterns. For squamous cell carcinoma, 4 of 7 specimens (57%) were correctly diagnosed. For the remaining 3 squamous cell carcinoma specimens, the solid pattern was correctly diagnosed in 2 additional cases (29%), but it was not possible to distinguish the squamous cell carcinoma from adenocarcinoma. The other squamous cell carcinoma specimen (1 of 7; 14%) was misdiagnosed as adenocarcinoma because of pseudogland formation. Invasive adenocarcinomas with acinar and solid pattern showed statistically significant increases in collagen. Interobserver agreement for collagen quantification (among 3 observers) was 80%. CONCLUSIONS: Our pilot study provides a proof of principle that MPM can differentiate neoplastic from nonneoplastic lung tissue and identify tumor subtypes. If confirmed in a future, larger study, we foresee real-time intraoperative applications of MPM, using miniaturized instruments for directing lung biopsies, assessing their adequacy for subsequent histopathologic analysis or banking, and evaluating surgical margins in limited lung resections.

Full-field optical coherence tomography for the analysis of fresh unstained human lobectomy specimens.

BACKGROUND: Full-field optical coherence tomography (FFOCT) is a real-time imaging technique that generates high-resolution three-dimensional tomographic images from unprocessed and unstained tissues. Lack of tissue processing and associated artifacts, along with the ability to generate large-field images quickly, warrants its exploration as an alternative diagnostic tool. MATERIALS AND METHODS: One section each from the tumor and from adjacent non-neoplastic tissue was collected from 13 human lobectomy specimens. They were imaged fresh with FFOCT and then submitted for routine histopathology. Two blinded pathologists independently rendered diagnoses based on FFOCT images. RESULTS: Normal lung architecture (alveoli, bronchi, pleura and blood vessels) was readily identified with FFOCT. Using FFOCT images alone, the study pathologists were able to correctly identify all tumor specimens and in many cases, the histological subtype of tumor (e.g., adenocarcinomas with various patterns). However, benign diagnosis was provided with high confidence in roughly half the tumor-free specimens (others were diagnosed as equivocal or false positive). Further analysis of these images revealed two major confounding features: (a) Extensive lung collapse and (b) presence of smoker's macrophages. On a closer inspection, however, the smoker's macrophages could often be identified as distinct from tumor cells based on their relative location in the alveoli, size and presence of anthracosis. We posit that greater pathologist experience, complemented with morphometric analysis and color-coding of image components, may help minimize the contribution of these confounders in the future. CONCLUSION: Our study provides evidence for the potential utility of FFOCT in identifying and differentiating lung tumors from non-neoplastic lung tissue. We foresee its potential as an adjunct to intra-surgical frozen section analysis for margin assessment, especially in limited lung resections.

Activation of HIF2α in kidney proximal tubule cells causes abnormal glycogen deposition but not tumorigenesis.

Renal cell carcinoma (RCC) is the most common primary cancer arising from the kidney in adults, with clear cell renal cell carcinoma (ccRCC) representing approximately 75% of all RCCs. Increased expression of the hypoxia-induced factors-1α (HIF1α) and HIF2α has been suggested as a pivotal step in ccRCC carcinogenesis, but this has not been thoroughly tested. Here, we report that expression of a constitutively activated form of HIF2α (P405A, P530A, and N851A, named as HIF2αM3) in the proximal tubules of mice is not sufficient to promote ccRCC by itself, nor does it enhance HIF1αM3 oncogenesis when coexpressed with constitutively active HIF1αM3. Neoplastic transformation in kidneys was not detected at up to 33 months of age, nor was increased expression of Ki67 (MKI67), γH2AX (H2AFX), or CD70 observed. Furthermore, the genome-wide transcriptome of the transgenic kidneys does not resemble human ccRCC. We conclude that a constitutively active HIF2α is not sufficient to cause neoplastic transformation of proximal tubules, arguing against the idea that HIF2α activation is critical for ccRCC tumorigenesis.

Functional outcomes following robotic prostatectomy using athermal, traction free risk-stratified grades of nerve sparing.

OBJECTIVE: To report our unique approach for individualizing robotic prostate cancer surgery by risk stratification and sub classification of the periprostatic space into 4 distinct compartments, and thus performing 4 precise different grades of nerve sparing based on neurosurgical principles and to present updated potency and continence outcomes data of patients undergoing robotic-assisted laparoscopic prostatectomy (RALP) using our risk-stratified approach based on layers of periprostatic fascial dissection. PATIENTS AND METHODS: (1) Between January 2005 and December 2010, 2,536 men underwent RALP by a single surgeon at our institution. (2) Included patients were those with ≥ 1-year follow-up and were preoperatively continent and potent, defined as having a SHIM questionnaire score of >21; thus, the final number of patient in the study cohort was 1,335. (3) Postoperative potency was defined as the ability to have successful intercourse (score of ≥ 4 on question 2 of the SHIM); continence was defined as the use of no pads per 24 h. RESULTS: (1) The potency and continence for NS grades 1, 2, 3, and 4 were found to be 90.6, 76.2, 60.5, and 57.1 % (P < 0.001) and 98, 93.2, 90.1, and 88.9 % (P < 0.001), respectively. (2) The overall PSM rates for patients with NS grades 1, 2, 3, and 4 were 10.5, 7, 5.8, and 4.8 %, respectively (P = 0.064). CONCLUSIONS: The study found a correlation between risk-stratified grades of NS technique and continence and potency. Patients with lesser grades of NS had higher rates of potency and continence.

Multiphoton tomographic imaging: a potential optical biopsy tool for detecting gastrointestinal inflammation and neoplasia.

Endoscopy is widely used to detect and remove premalignant lesions with the goal of preventing gastrointestinal (GI) cancers. Because current endoscopes do not provide cellular resolution, all suspicious lesions are biopsied and subjected to histologic evaluation. Technologies that facilitate directed biopsies should decrease both procedure-related morbidity and cost. Here we explore the use of multiphoton microscopy (MPM), an optical biopsy tool that relies on intrinsic tissue emissions, to evaluate pathology in both experimental and human GI specimens, using hematoxylin and eosin (H&E)-stained sections from these tissues for comparison. After evaluating the entire normal mouse GI tract, MPM was used to investigate disease progression in mouse models of colitis and colorectal carcinogenesis. MPM provided sufficient histologic detail to identify all relevant substructures in ex vivo normal GI tissue, visualize both acute and resolving stages of colitis, and show the progression of colorectal carcinogenesis. Next, ex vivo specimens from human subjects with celiac sprue, inflammatory bowel disease, and colorectal neoplasia were imaged by MPM. Finally, colonic mucosa in live anesthetized rats was imaged in vivo using a flexible endoscope prototype. In both animal models and human specimens, MPM images showed a striking similarity to the results of H&E staining, as shown by the 100% concordance achieved by the study pathologists' diagnoses. In summary, MPM is a promising technique that accurately visualizes histology in fresh, unstained tissues. Our findings support the continued development of MPM as a technology to enhance the early detection of GI pathologies including premalignant lesions.

Next-generation prostate cancer biobanking: toward a processing protocol amenable for the International Cancer Genome Consortium.

Next-generation DNA and RNA sequencing requires intact nucleic acids from high-quality human tissue samples to better elucidate the molecular basis of cancer. We have developed a prostate biobanking protocol to acquire suitable samples for sequencing without compromising the accuracy of clinical diagnosis. To assess the clinical implications of implementing this protocol, we evaluated 105 consecutive radical prostatectomy specimens from November 2008 to February 2009. Alternating levels of prostate samples were submitted to Surgical Pathology as formalin-fixed, paraffin-embedded blocks and to the institutional biobank as frozen blocks. Differences in reported pathologic characteristics between clinical and procured specimens were compared. Clinical staging and grading were not affected by the biobank protocol. Tumor foci on frozen hematoxylin and eosin slides were identified and high-density tumor foci were scored and processed for DNA and RNA extractions for sequencing. Both DNA and RNA were extracted from 22 cases of 44 with high-density tumor foci. Eighty-two percent (18/22) of the samples passed rigorous quality control steps for DNA and RNA sequencing. To date, DNA extracted from 7 cases has undergone whole-genome sequencing, and RNA from 18 cases has been RNA sequenced. This protocol provides prostate tissue for high-throughput biomedical research and confirms the feasibility of actively integrating prostate cancer into The Cancer Genome Atlas Program, a member of the International Cancer Genome Consortium.

Anatomical grades of nerve sparing: a risk-stratified approach to neural-hammock sparing during robot-assisted radical prostatectomy (RARP).

OBJECTIVES: • To report the potency and oncological outcomes of patients undergoing robot-assisted radical prostatectomy (RARP) using a risk-stratified approach based on layers of periprostatic fascial dissection. • We also describe the surgical technique of complete hammock preservation or nerve sparing grade 1. PATIENTS AND METHODS: • This is a retrospective study of 2317 patients who had robotic prostatectomy by a single surgeon at a single institution between January 2005 and June 2010. • Included patients were those with ≥ 1 year of follow-up and who were potent preoperatively, defined as having a sexual health inventory for men (SHIM) questionnaire score of >21; thus, the final number of patients in the study cohort was 1263. • Patients were categorized pre-operatively by a risk-stratified approach into risk grades 1-4, where risk grade 1 patients received nerve-sparing grade 1 or complete hammock preservation and so on for risk grades 2-4, as long as intraoperative findings permitted the planned nerve sparing. • We considered return to sexual function post-operatively by two criteria: i) ability to have successful intercourse (score of ≥ 4 on question 2 of the SHIM) and ii) SHIM >21 or return to baseline sexual function. RESULTS: • There was a significant difference across different NS grades in terms of the percentages of patients who had intercourse and returned to baseline sexual function (P < 0.001), with those that underwent NS grade 1 having the highest rates (90.9% and 81.7%) as compared to NS grades 2 (81.4% and 74.3%), 3 (73.5% and 66.1%), and 4 (62% and 54.5%). • The overall positive surgical margin (PSM) rates for patients with NS grades 1, 2, 3, and 4 were 9.9%, 8.1%, 7.2%, and 8.7%, respectively (P = 0.636). • The extraprostatic extension rates were 11.6%, 14.3%, 29.3%, and 36.2%, respectively (P < 0.001). • Similarly, in patients younger than 60, intercourse and return to baseline sexual function rates were 94.9% and 84.3% for NS grade 1 as compared to 85.5% and 77.2% for NS grades 2, 76.9% and 69% for NS grades 3, and 64.8% and 57.7% for NS Grade 4 (P < 0.001). CONCLUSIONS: • The risk-stratified approach and anatomical technique of neural-hammock sparing described in the present manuscript was effective in improving potency outcomes of patients without compromising cancer control. • Patients with greater degrees of NS had higher rates of intercourse and return to baseline sexual function without an increase in PSM rates.

Generation of a mouse model of Von Hippel-Lindau kidney disease leading to renal cancers by expression of a constitutively active mutant of HIF1α.

Renal cancers are highly aggressive and clinically challenging, but a transgenic mouse model to promote pathologic studies and therapeutic advances has yet to be established. Here, we report the generation of a transgenic mouse model of von Hippel-Lindau (VHL) renal cancer termed the TRACK model (transgenic model of cancer of the kidney). TRACK mice specifically express a mutated, constitutively active HIF1α in kidney proximal tubule (PT) cells. Kidney histologies displayed by TRACK mice are highly similar to histologies seen in patients with VHL disease, including areas of distorted tubular structure, cells with clear cytoplasm and increased glycogen and lipid deposition, multiple renal cysts, and early onset of clear cell renal cell carcinoma (ccRCC). Distorted tubules in TRACK mice exhibit higher levels of CA-IX, Glut1, and VEGF than tubules in nontransgenic control mice. Furthermore, these tubules exhibit increased numbers of endothelial cells, increased cell proliferation, and increased expression of the human ccRCC marker CD70(TNFSF7). Moreover, PT cells in kidney tubules from TRACK mice exhibit increased genomic instability, as monitored by elevated levels of γH2AX. Our findings establish that activated HIF1α in murine kidney PT cells is sufficient to promote cell proliferation, angiogenesis, genomic instability, and other phenotypic alterations characteristic of human VHL kidney disease, establishing the TRACK mouse as a valid preclinical model of human renal cell carcinoma.

Multiphoton microscopy for structure identification in human prostate and periprostatic tissue: implications in prostate cancer surgery.

OBJECTIVE: • To test whether multiphoton microscopy (MPM) might allow identification of prostatic and periprostatic structures with magnification and resolution similar to gold standard histopathology. MATERIAL AND METHODS: • The present study included 95 robotic radical prostatectomy patients who consented to participate in an Institutional Review Board-approved study starting in 2007. • The types of specimens used for imaging were excised surgical margins and biopsies, and sections obtained from the excised prostate. • The specimens were imaged with a custom-built MPM system. • All images were compared with haematoxylin/eosin histopathology of the same specimen. RESULTS: • MPM of freshly excised, unprocessed and unstained tissue can identify all relevant prostatic and periprostatic structures, such as nerves, blood vessels, capsule, underlying acini and also pathological changes, including prostate cancer. • Histological confirmation and correlation of these structures and pathologies have validated the findings of MPM. CONCLUSIONS: • MPM shows great promise as a tool for real-time intra-surgical histopathology without needing excision or administration of contrast agents. • The results will, however, need to be confirmed in true surgical settings using a miniaturized MPM microendoscope.

Visual cues as a surrogate for tactile feedback during robotic-assisted laparoscopic prostatectomy: posterolateral margin rates in 1340 consecutive patients.

OBJECTIVE: To analyse consecutive cases of robotic-assisted laparoscopic prostatectomy (RALP), present the incidence of nerve-sparing-related positive surgical margins (SM+), include visual cues that might assist in smoothly changing to the robotic platform, and discuss the scientific rationale for 'intersensory integration' which might explain the 'reverse Braille' phenomenon, i.e. the ability to feel when vision is greatly enhanced, as the lack of tactile feedback during RALP is often cited as a disadvantage of robotic surgery, interfering with a surgeon's ability to make intraoperative oncological decisions. PATIENTS AND METHODS: Data from 1340 consecutive patients undergoing RALP from one institution were analysed and trends for positive posterolateral SM+ (PLSM+) were correlated with oncological variables before and after RALP. A sample of patient slides were reviewed by a extramural pathologist. Multivariate regression modelling was used to compare the projected rates of PLSM+ vs the actual rate, given the effect of a conscious effort to use visual cues. Finally, video recordings of the procedure were systematically reviewed and correlated with anatomical and histopathological images in an integrated session involving the surgeon and the pathology team. RESULTS: The incidence of PLSM+ was 2.1%, which gradually declined to 1.0% in the last 100 patients. The reduction in PLSM+ occurred despite an increased rate of high-risk tumours operated on during this period. Forecasting analysis showed that the actual PLSM+ rate declined by half in the most recent 1000 patients, due to an integrated effort involving the use of visual cues during surgery. The following visual cues were considered important; appreciation of periprostatic (lateral prostatic) fascial compartments; colour and texture of the tissue; periprostatic veins as a landmark for athermal dissection; signs of inflammation; and a freely separating bloodless plane showing loose shiny areolar tissue. CONCLUSION: Adapting to the robotic platform is easy and there is no compromise of the oncological safety of this procedure. Experienced surgeons can use visual cues to assist during nerve-sparing RALP and achieve low PLSM+ rates.

Proliferative extensor tenosynovitis of the wrist in the absence of rheumatoid arthritis.

PURPOSE: Proliferative tenosynovitis in the fourth extensor compartment is common in patients with rheumatoid arthritis. It may also occur in the absence of rheumatoid arthritis; the purpose of this study is to describe this clinical condition in a series of patients, to report the results of surgical intervention, and to compare histological findings to those typically seen in rheumatoid tenosynovitis. METHODS: This study presents a retrospective case series of 11 patients who do not have rheumatoid arthritis, who had proliferative tenosynovitis of the fourth extensor compartment treated surgically. Relevant features of the clinical presentation, physical examination, radiographic findings, and results of attempts at conservative treatment are described. Surgical pathology specimens were reviewed by a single pathologist to define common histological features and to compare the histology to that which is classically seen in rheumatoid tenosynovitis. RESULTS: All patients presented with a painful wrist mass over the fourth extensor compartment. Characteristic in physical examination was severe limitation of active wrist extension with the fingers extended, with improvement when the fingers were flexed into a fist. After tenosynovectomy, wrist extension and grip strength improved. Examination of the surgical pathology specimens revealed a spectrum of pathological findings generally consistent with traumatic tenosynovitis, but a few specimens had rheumatoid-like features. CONCLUSIONS: A review of this case series of patients with tenosynovitis but without rheumatoid arthritis demonstrates a distinct clinical condition of exuberant proliferative extensor tenosynovitis blocking proximal tendon excursion, thereby causing pain and limited active wrist extension, as well as a less distinct histological condition with a constellation of findings generally resembling traumatic tenosynovitis. In this group of patients, surgical tenosynovectomy generally yields excellent results. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.