Advances, recognition, and interpretation of molecular heterogeneity among conventional and subtype histology of urothelial carcinoma (UC): a survey among urologic pathologists and comprehensive review of the literature.

AIMS: Urothelial carcinoma (UC) demonstrates significant molecular and histologic heterogeneity. The WHO 2022 classification has hinted at adding molecular signatures to the morphologic diagnosis. As morphology and associated molecular repertoire may potentially translate to choices of and response to therapy and relapse rate, broader acceptability of recognizing these key features among uropathologists is needed. This prompted an international survey to ascertain the practice patterns in classical/subtype UC among uropathologists across the globe. METHODS AND RESULTS: A survey instrument was shared among 98 uropathologists using SurveyMonkey software. Anonymized respondent data were analysed. The response rate was 85%. A majority were in concordance with the profiles of luminal (93%) and basal (82%) types. Opinion on the FGFR3 testing platform was variable. While 95% concurred that TERT promoter mutation is the key driver in UC, 72% had the opinion that APOBEC mutagenesis is the main signature in muscle invasive bladder cancer (MIBC). Uropathologists have divergent opinions on MIBC and ERCC2 mutations. Among the participants, 94% would quantify aggressive micropapillary and sarcomatoid histology, while 88% would reevaluate another transurethral resection of the bladder tumour specimen in nonmuscle invasive tumour with micropapillary, small cell, or sarcomatoid histology. A leading number agreed to specific molecular signatures of micropapillary (93%), plasmacytoid (97%), and small cell (86%) subtypes. Ninety-six percent of participants agreed that a small-cell component portends a more aggressive course and should be treated with neoadjuvant chemotherapy and 63% would perform HER2/neu testing only on oncologist's request in advanced tumours. Ninety percent agreed that microsatellite instability testing, although not a standard protocol, should be considered in young patients with upper tract UC. Eighty-six percent agreed that UC with high tumour mutational burden would be a better candidate for immunotherapy. CONCLUSION: In the era of precision medicine, enhanced understanding of molecular heterogeneity of UC will contribute to better therapeutic options, novel biomarker discovery, innovative management protocols, and outcomes. Our survey provides a broad perspective of pathologists' perceptions and experience regarding incorporation of histomolecular approaches to "personalize" therapy. Due to variable clinical adoption, there is a need for additional data using uniform study criteria. This will drive generation of best practice guidelines in this area for widespread and consistent clinical utility.

Polyoma virus-associated carcinomas of the urologic tract: a clinicopathologic and molecular study.

In recent years, there has been increased interest in carcinomas of the urologic tract, that demonstrate association with the polyoma virus BK arising in immunosuppressed individuals, though the nature of this association is uncertain. To begin to understand this phenomenon, we reviewed the clinical, morphological, and immunohistochemical features of 11 carcinomas of the urologic tract, mainly urothelial (N = 9) and collecting duct carcinomas (N = 2), occurring during immunosuppression, and expressing polyoma virus T-antigen by immunohistochemistry. These were compared to a control group of carcinomas (N = 8), also arising during immunosuppression, but without T-antigen expression. A subset of both groups were also studied by hybrid capture-based DNA sequencing, probing not only for 479 cancer-related human genes, but also for polyoma and other viral sequences. Polyoma T-antigen-expressing tumors arose in 7 males and 4 females, at a median age of 66, and were aggressive, high-grade tumors with more than 1 variant morphologic pattern identified in 81% of cases, and a majority (73%) presenting at high stage category (>pT3). Diffuse polyoma T-antigen staining was seen in 91% of cases, with co-localization of aberrant p53 staining in 89%. Sequencing detected a lower number of deleterious mutations among T-antigen-expressing cases (average 1.62; 1/8 with TP53 mutation) compared to control cases (average 3.5, 2/4 with TP53 mutation). Only BK virus was detected with clonal integration and breakpoints randomly distributed across the human and viral genomes in 5/5 of the polyoma T-antigen-expressing carcinomas, and in none of the controls (0/4). In summary, these findings identify aggressive clinicopathologic features of polyoma T-antigen-expressing carcinomas, document BK as the strain involved, and associate BK viral integration with T-antigen expression and p53 aberrancy. While the apparent randomness of viral insertion sites is functionally unclear, the differing rates of mutations between T-antigen-expressing and control cases is intriguing.

A distinctive, low-grade oncocytic fumarate hydratase-deficient renal cell carcinoma, morphologically reminiscent of succinate dehydrogenase-deficient renal cell carcinoma.

AIMS: Fumarate hydratase (FH)-deficient renal cell carcinoma (RCC) is a high-grade, aggressive tubulopapillary carcinoma, arising predominantly in the setting of the hereditary leiomyomatosis-RCC syndrome of familial uterocutaneous leiomyomatosis and deficiency of FH. In contrast, succinate dehydrogenase (SDH)-deficient RCC is a lower-grade oncocytic carcinoma with cytoplasmic flocculence/vacuolation and inclusions, arising mostly in individuals harbouring germline mutations of subunit B of the SDH complex (SDHB). Herein we aim to report the clinicopathologic features of a novel form of FH-deficient RCC showing a low grade oncocytic morphology, reminiscent of SDH-deficient RCC. METHODS AND RESULTS: These distinctive, low-grade oncocytic neoplasms, with solid, nested and focally tubular architecture (2-90 mm), arose in four males (aged 11-41 years). Uniform cytology of polygonal cells, with flocculent, vacuolated eosinophilic cytoplasm with scattered inclusions, fine chromatin, and inconspicuous nucleoli, was apparent. Despite these features suggestive of SDH-deficient RCC, each tumour was confirmed as an FH-deficient carcinoma with retained SDHB expression. One case showed a synchronous, anatomically separate, typical high-grade FH-deficient RCC; one other showed such a tumour at nephrectomy 4 years later. No progression has been noted at 3 and 7 years in the cases with only the SDH-like lesions; the two cases with separate, typical FH-deficient RCCs progressed. CONCLUSIONS: In summary, we characterize a novel oncocytic type of FH-deficient RCC with a striking resemblance to SDH-deficient RCC, posing a diagnostic challenge and raising concerns about sampling and multifocality for syndrome-associated cases under surveillance protocols.

Subclassification of prostate cancer circulating tumor cells by nuclear size reveals very small nuclear circulating tumor cells in patients with visceral metastases.

BACKGROUND: Although enumeration of circulating tumor cells (CTCs) has shown some clinical value, the pool of CTCs contains a mixture of cells that contains additional information that can be extracted. The authors subclassified CTCs by shape features focusing on nuclear size and related this with clinical information. METHODS: A total of 148 blood samples were obtained from 57 patients with prostate cancer across the spectrum of metastatic states: no metastasis, nonvisceral metastasis, and visceral metastasis. CTCs captured and enumerated on NanoVelcro Chips (CytoLumina, Los Angeles, Calif) were subjected to pathologic review including nuclear size. The distribution of nuclear size was analyzed using a Gaussian mixture model. Correlations were made between CTC subpopulations and metastatic status. RESULTS: Statistical modeling of nuclear size distribution revealed 3 distinct subpopulations: large nuclear CTCs, small nuclear CTCs, and very small nuclear CTCs (vsnCTCs). Small nuclear CTCs and vsnCTC identified those patients with metastatic disease. However, vsnCTC counts alone were found to be elevated in patients with visceral metastases when compared with those without (0.36 ± 0.69 vs 1.95 ± 3.77 cells/mL blood; P<.001). Serial enumeration studies suggested the emergence of vsnCTCs occurred before the detection of visceral metastases. CONCLUSIONS: There are morphologic subsets of CTCs that can be identified by fundamental pathologic approaches, such as nuclear size measurement. The results of this observational study strongly suggest that CTCs contain relevant information regarding disease status. In particular, the detection of vsnCTCs was found to be correlated with the presence of visceral metastases and should be formally explored as a putative blood-borne biomarker to identify patients at risk of developing this clinical evolution of prostate cancer.

Uroplakin II outperforms uroplakin III in diagnostically challenging settings.

AIMS: We performed a head-to-head comparison of an antibody against uroplakin III (UP3) and a new uroplakin II (UP2) antibody that remains untested in diagnostically challenging settings. METHODS AND RESULTS: We immunostained high-grade bladder neck carcinomas (n = 35), high-grade upper tract urothelial carcinomas (UC) and renal carcinomas (n = 85), metastases of UC (n = 30) and a multicancer tissue microarray (n = 88) for UP3 and UP2, and scored staining intensity and proportion. UP3 showed membranous plaque-like expression, while UP2 staining showed both membranous and cytoplasmic positivity. Significantly greater intensity (P = 0.003) and proportion (P = 0.03) of staining was noted for UP2 among bladder neck lesions, with UP2 staining showing greater sensitivity (63% versus 19%) and similar specificity (95% versus 100%) for UC over prostate carcinoma (P = 0.02). Among upper tract lesions, UP2 staining showed greater intensity and proportion than UP3 (both P < 0.001), including improved sensitivity (68% versus 23%) and equal specificity (both 100%) for UC (P = 0.006). Among UC metastases, UP2 staining showed greater intensity and proportion (both P < 0.001) with higher sensitivity (73% versus 37%, respectively, P = 0.001). Of 88 additional cases tested, no non-urothelial cases stained for either UP. CONCLUSIONS: The UP2 antibody outperforms the UP3 antibody, including in diagnostically challenging settings, and is a useful addition to the armamentarium of biomarkers for UC.

Threonine-120 phosphorylation regulated by phosphoinositide-3-kinase/Akt and mammalian target of rapamycin pathway signaling limits the antitumor activity of mammalian sterile 20-like kinase 1.

Mst1/Stk4, a hippo-like serine-threonine kinase, is implicated in many cancers, including prostate cancer. However, the mechanisms regulating Mst1 remain obscure. Here, we characterized the effects of phospho-Thr-120 on Mst1 in prostate cancer cells. We demonstrated that phospho-Thr-120 did not alter the nuclear localization or cleavage of Mst1 in a LNCaP or castration-resistant C4-2 prostate tumor cell model, as revealed by a mutagenesis approach. Phospho-Thr-120 appeared to be specific to cancer cells and predominantly localized in the nucleus. In contrast, phospho-Thr-183, a critical regulator of Mst1 cell death, was exclusively found in the cytoplasm. As assessed by immunohistochemistry, a similar distribution of phospho-Mst1-Thr-120/Thr-183 was also observed in a prostate cancer specimen. In addition, the blockade of PI3K signaling by a small molecule inhibitor, LY294002, increased cytoplasmic phospho-Mst1-Thr-183 without having a significant effect on nuclear phospho-Mst1-Thr-120. However, the attenuation of mammalian target of rapamycin (mTOR) activity by a selective pharmacologic inhibitor, Ku0063794 or CCI-779, caused the up-regulation of nuclear phospho-Mst1-Thr-120 without affecting cytoplasmic phospho-Mst1-Thr-183. This suggests that PI3K and mTOR pathway signaling differentially regulate phospho-Mst1-Thr-120/Thr-183. Moreover, mutagenesis and RNAi data revealed that phospho-Thr-120 resulted in C4-2 cell resistance to mTOR inhibition and reduced the Mst1 suppression of cell growth and androgen receptor-driven gene expression. Collectively, these findings indicate that phospho-Thr-120 leads to the loss of Mst1 functions, supporting cancer cell growth and survival.

The effects of glycemic index on prostate cancer progression in a xenograft mouse model.

BACKGROUND: Previously, we found low-carbohydrate diets slowed prostate cancer (PC) growth and increased survival vs. a Western diet in mice, by inhibiting the insulin/IGF-1 axis. Thus, we tested whether modifying carbohydrate quality to lower glycemic index (GI) without changing quantity results in similar benefits as with reduced quantity. METHODS: Male SCID mice injected with LAPC-4 cells were single-housed and randomized when their tumors reached 200 mm3 on average to a LoGI (48% carbohydrate kcal, from Hylon-VII) or HiGI Western diet (48% carbohydrate kcal, from sucrose). Body weight and tumor volume were measured weekly. Body composition was assessed 35 days after randomization. Blood glucose and serum insulin, IGF-1 and IGFBP3 were measured at study end when tumor volumes reached 800 mm3. We analyzed gene expression of mice tumors by RNA-sequencing and human tumors using the Prostate Cancer Transcriptome Atlas. RESULTS: There were no significant differences in tumor volume (P > 0.05), tumor proliferation (P = 0.29), and overall survival (P = 0.15) between groups. At 35 days after randomization, the LoGI group had 30% lower body fat (P = 0.007) despite similar body weight (P = 0.58). At sacrifice, LoGI mice had smaller livers (P < 0.001) and lower glucose (P = 0.15), insulin (P = 0.11), IGF-1 (P = 0.07) and IGF-1:IGFBP3 ratio (P = 0.05), and higher IGFBP3 (P = 0.09) vs. HiGI, although none of these metabolic differences reached statistical significance. We observed differential gene expression and pathway enrichment in mice tumors by diet. The most upregulated and downregulated gene in the LoGI group showed expression patterns more closely resembling expression in human benign prostate tissue vs. PC. CONCLUSIONS: In this single mouse xenograft model, consuming a low GI diet did not delay PC growth or survival vs. a high GI diet despite suggestions of decreased activation of the insulin/IGF-1 pathway. These data suggest that improving carbohydrate quality alone while consuming a high carbohydrate diet may not effectively slow PC growth.

Macrophage angiotensin-converting enzyme reduces atherosclerosis by increasing peroxisome proliferator-activated receptor α and fundamentally changing lipid metabolism.

AIMS: The metabolic failure of macrophages to adequately process lipid is central to the aetiology of atherosclerosis. Here, we examine the role of macrophage angiotensin-converting enzyme (ACE) in a mouse model of PCSK9-induced atherosclerosis. METHODS AND RESULTS: Atherosclerosis in mice was induced with AAV-PCSK9 and a high-fat diet. Animals with increased macrophage ACE (ACE 10/10 mice) have a marked reduction in atherosclerosis vs. WT mice. Macrophages from both the aorta and peritoneum of ACE 10/10 express increased PPARα and have a profoundly altered phenotype to process lipids characterized by higher levels of the surface scavenger receptor CD36, increased uptake of lipid, increased capacity to transport long chain fatty acids into mitochondria, higher oxidative metabolism and lipid ß-oxidation as determined using 13C isotope tracing, increased cell ATP, increased capacity for efferocytosis, increased concentrations of the lipid transporters ABCA1 and ABCG1, and increased cholesterol efflux. These effects are mostly independent of angiotensin II. Human THP-1 cells, when modified to express more ACE, increase expression of PPARα, increase cell ATP and acetyl-CoA, and increase cell efferocytosis. CONCLUSION: Increased macrophage ACE expression enhances macrophage lipid metabolism, cholesterol efflux, efferocytosis, and it reduces atherosclerosis. This has implications for the treatment of cardiovascular disease with angiotensin II receptor antagonists vs. ACE inhibitors.

Prostate cancer extracellular vesicle digital scoring assay - a rapid noninvasive approach for quantification of disease-relevant mRNAs.

Optimizing outcomes in prostate cancer (PCa) requires precision in characterization of disease status. This effort was directed at developing a PCa extracellular vesicle (EV) Digital Scoring Assay (DSA) for detecting metastasis and monitoring progression of PCa. PCa EV DSA is comprised of an EV purification device (i.e., EV Click Chip) and reverse-transcription droplet digital PCR that quantifies 11 PCa-relevant mRNA in purified PCa-derived EVs. A Met score was computed for each plasma sample based on the expression of the 11-gene panel using the weighted Z score method. Under optimized conditions, the EV Click Chips outperformed the ultracentrifugation or precipitation method of purifying PCa-derived EVs from artificial plasma samples. Using PCa EV DSA, the Met score distinguished metastatic (n = 20) from localized PCa (n = 20) with an area under the receiver operating characteristic curve of 0.88 (95% CI:0.78-0.98). Furthermore, longitudinal analysis of three PCa patients showed the dynamics of the Met scores reflected clinical behavior even when disease was undetectable by imaging. Overall, a sensitive PCa EV DSA was developed to identify metastatic PCa and reveal dynamic disease states noninvasively. This assay may complement current imaging tools and blood-based tests for timely detection of metastatic progression that can improve care for PCa patients.

Oncocytoma of the kidney with prominent intracytoplasmic lumina.

Oncocytoma is a histologically distinctive neoplasm of the kidney, with a well-recognized cytoarchitectural appearance. On occasion, however, renal oncocytomas are known to exhibit unusual morphologic features that may pose diagnostic difficulties. We present the clinical and pathologic details of an oncocytoma of the kidney with an unusual histologic appearance imparted by the presence of large numbers of prominent intracytoplasmic lumens. Morphologically, the neoplasm was composed of uniform polygonal cells with copious amounts of granular, eosinophilic cytoplasm, round nuclei, and prominent nucleoli, exhibiting an organoid pattern of growth. Intracytoplasmic lumina of varying size were present throughout the tumor. There were no mitotic figures or areas of necrosis present. The diagnosis of oncocytoma was supported by immunohistochemical and ultrastructural studies. By electron microscopy, the intracytoplasmic lumens appeared as membrane bound spaces with associated microvilli. The presence of intracytoplasmic lumina in a significant proportion of cells is an uncommon feature of renal oncocytoma which can generate problems in diagnosis. Awareness of this phenomenon should allow for improved recognition of oncocytomas exhibiting this type of unusual morphology.

Amyloidosis of the bladder and association with urothelial carcinoma: report of 29 cases.

The association of amyloidosis with certain neoplastic processes is well known. Amyloid uncommonly occurs in relationship with other epithelial neoplasms including urothelial carcinoma. Herein, we report 29 cases of amyloidosis in the bladder, 14 of which were found in relationship to urothelial carcinoma. With institutional review board approval. We searched pathology archives for cases of amyloidosis in the bladder. Clinical, laboratory, and surgical pathology records were reviewed, and data were recorded for all cases. Diagnosis of amyloid was made by Congo red stain showing apple-green birefringence on polarization microscopy and special studies in some cases. Twenty-nine cases of amyloid were identified in bladder specimens. Presentation as a mass lesion was the most common (n = 18). Immunohistochemical subtyping done in 17 cases showed transthyretin-type (n = 10), AL (n = 3), AA (n = 1), amyloid P (n = 1), and undetermined (n = 2) types of amyloid. Eighteen (62%) cases were classified as localized primary amyloidosis and 11 (38%) as secondary manifestation of systemic amyloidosis. In 14 (48%) cases, there was an associated urothelial carcinoma: 5 urothelial carcinoma in situ, 4 low-grade noninvasive papillary urothelial carcinoma, 2 high-grade noninvasive papillary urothelial carcinoma, and 3 high-grade invasive urothelial carcinoma. Associated urothelial carcinoma was present in 4 of 7 patients with systemic amyloidosis and 10 of 18 patients with localized amyloidosis, with the difference not being statistically significant (P = .45). Amyloidosis of the bladder is rare and presents as a mucosal mass or hematuria that may mimic urothelial carcinoma. In this study, we found urothelial carcinoma occurring in 48% of the cases in association with amyloidosis, a finding not previously reported. The relationship of amyloid in the bladder and urothelial carcinoma, although likely not causal, appears to be a unique finding not frequently seen with other solid tumors.

Pulmonary capillary hemangiomatosis: a lesson learned.

Pulmonary capillary hemangiomatosis (PCH) is a rare and controversial entity that is known to be a cause of pulmonary hypertension and is microscopically characterized by proliferation of dilated capillary-sized channels along and in the alveolar walls. Clinically, it is mostly seen in adults. Clinical features are characterized by nonspecific findings such as shortness of breath, cough, chest pain, and fatigue. It can be clinically indistinguishable from pre-capillary pulmonary arterial hypertension disorders such as primary pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension. However, the diagnostic distinction, which usually requires a multidisciplinary approach, is crucial in order to avoid inappropriate treatment with vasodilator medications usually used for PAH treatment. Prognosis of PCH remains poor with lung transplant being the only definitive treatment. We report an autopsy case of pulmonary capillary hemangiomatosis unmasked at autopsy that was treated with a prostacyclin analog, usually contraindicated in such patients. We emphasize that this entity should always be on the differential diagnosis in a patient with pulmonary hypertension and requires great vigilance on the part of the clinician, radiologist and pathologist to make the diagnosis and guide appropriate management.

Pathology and Pathogenesis of Chagas Heart Disease.

Chagas heart disease is an inflammatory cardiomyopathy that develops in approximately one-third of people infected with the protozoan parasite Trypanosoma cruzi. One way T. cruzi is transmitted to people is through contact with infected kissing bugs, which are found in much of the Western Hemisphere, including in vast areas of the United States. The epidemiology of T. cruzi and Chagas heart disease and the varied mechanisms leading to myocyte destruction, mononuclear cell infiltration, fibrosis, and edema in the heart have been extensively studied by hundreds of scientists for more than 100 years. Despite this wealth of knowledge, it is still impossible to predict what will happen in an individual infected with T. cruzi because of the tremendous variability in clonal parasite virulence and human susceptibility to infection and the lack of definitive molecular predictors of outcome from either side of the host-parasite equation. Further, while several distinct mechanisms of pathogenesis have been studied in isolation, it is certain that multiple coincident mechanisms combine to determine the ultimate outcome. For these reasons, Chagas disease is best considered a collection of related but distinct illnesses. This review highlights the pathology and pathogenesis of the most common adverse sequela of T. cruzi infection-Chagas heart disease-and concludes with a discussion of key unanswered questions and a view to the future.

Bi-atrial cardiac myxoma with glandular differentiation: a case report with detailed radiologic-pathologic correlation.

INTRODUCTION: Myxoma is the most common cardiac benign tumour. While a typical myxoma is generally a straightforward diagnosis, some myxomas have unusual features that can make the diagnosis challenging. Glandular myxomas and metastatic adenocarcinomas, the most common type of metastatic carcinoma to the heart, can have very similar features. CASE PRESENTATION: We report a 60-year old man who presented with progressive shortness of breath on exertion. Echocardiography demonstrated a large heterogeneous, cystic left and right atrial mass. He was referred for surgery where a smooth and multilobulated left atrial mass was excised. Histopathological analysis with special stains revealed an unusual form of cardiac myxoma with extensive glandular differentiation. DISCUSSION: Cardiac myxomas can present with diverse clinical, radiological, and pathological features. Echocardiography is a modality of choice for diagnosis but can also miss small or multiple masses. Cardiac myxoma with glandular features is a rare type of myxoma. In our case, there was extensive glandular differentiation and the echocardiographic appearance provided clues for the unusual features of the tumour, suggesting a potential role for echocardiography in the detection and recognition of this morphologic histologic variation.

STAT3 and STAT5A are potential therapeutic targets in castration-resistant prostate cancer.

Mechanisms of castration-resistant prostate cancer (CRPC) are not well understood, thus hindering rational-based drug design. Activation of STAT3/5A, key components of the JAK/STAT pathway, is implicated in aggressive PC, yet their clinical relevance in CRPC remains elusive. Here, we evaluated the possible role of STAT3/5A in CRPC using immunological, quantitative mRNA expression profiling, and pharmacological methods. We observed a strong nuclear immunoreactivity for STAT3 and STAT5A in 93% (n=14/15) and 80% (n=12/15) of CRPC cases, respectively, compared with benign prostatic hyperplasia (BPH). We demonstrated that PC cells express varying levels of STAT3 and STAT5A transcripts. In addition, we demonstrate that pimozide, a psychotropic drug and an indirect inhibitor of STAT5, attenuated PC cells growth, and induced apoptosis in a dose-dependent manner. Furthermore, our analysis of the PC public data revealed that the STAT3/5A genes were frequently amplified in metastatic CRPC. These findings suggest that STAT3/5A potentially serves as a predictive biomarker to evaluate the therapeutic efficacy of a cancer drug targeting the JAK/STAT pathway. Since the JAK/STAT and AR pathways are suggested to be functionally synergistic, inhibition of the JAK/STAT signaling alone or together with AR may lead to a novel treatment modality for patients with advanced PC.

Pathology of Chronic Chagas Cardiomyopathy in the United States: A Detailed Review of 13 Cardiectomy Cases.

OBJECTIVES: The pathologic features of chronic Chagas cardiomyopathy may not be widely appreciated in the United States. We sought to describe the gross, microscopic, immunohistochemical, and molecular pathology features useful to diagnose chronic Chagas cardiomyopathy. METHODS: The features from a case series of cardiectomy specimens of patients undergoing heart transplantation (12 patients) or mechanical circulatory support device implantation (one patient) for chronic Chagas cardiomyopathy at three institutions in the United States are reported and analyzed. RESULTS: Gross findings included enlarged and dilated ventricles (100% of cases), mural thrombi (54%), epicardial plaques (42%), and left ventricular aneurysm (36%). Microscopic evaluation revealed myocarditis (100% of cases) characterized by mononuclear cell infiltration, fibrosis (100%), nonnecrotizing granulomas (62%), and giant cells (38%). Two specimens (15%) showed rare intracellular amastigotes. Immunohistochemical assays for Trypanosoma cruzi organisms were negative in all cardiectomy specimens, whereas tissue polymerase chain reaction was positive in six (54%) of 11 cases. CONCLUSIONS: The gross and microscopic features of chronic Chagas cardiomyopathy in the United States appear similar to those reported in endemic countries. Importantly, tissue polymerase chain reaction may be useful to confirm the diagnosis.

Quantitative imaging for development of companion diagnostics to drugs targeting HGF/MET.

The limited clinical success of anti-HGF/MET drugs can be attributed to the lack of predictive biomarkers that adequately select patients for treatment. We demonstrate here that quantitative digital imaging of formalin fixed paraffin embedded tissues stained by immunohistochemistry can be used to measure signals from weakly staining antibodies and provides new opportunities to develop assays for detection of MET receptor activity. To establish a biomarker panel of MET activation, we employed seven antibodies measuring protein expression in the HGF/MET pathway in 20 cases and up to 80 cores from 18 human cancer types. The antibodies bind to epitopes in the extra (EC)- and intracellular (IC) domains of MET (MET4EC, SP44_METIC, D1C2_METIC), to MET-pY1234/pY1235, a marker of MET kinase activation, as well as to HGF, pSFK or pMAPK. Expression of HGF was determined in tumour cells (T_HGF) as well as in stroma surrounding cancer (St_HGF). Remarkably, MET4EC correlated more strongly with pMET (r = 0.47) than SP44_METIC (r = 0.21) or D1C2_METIC (r = 0.08) across 18 cancer types. In addition, correlation coefficients of pMET and T_HGF (r = 0.38) and pMET and pSFK (r = 0.56) were high. Prediction models of MET activation reveal cancer-type specific differences in performance of MET4EC, SP44_METIC and anti-HGF antibodies. Thus, we conclude that assays to predict the response to HGF/MET inhibitors require a cancer-type specific antibody selection and should be developed in those cancer types in which they are employed clinically.