Catherine M. Conway

Sporadic naturally occurring melanoma in dogs as a preclinical model for human melanoma

Melanoma represents a significant malignancy in humans and dogs. Different from genetically engineered models, sporadic canine melanocytic neoplasms share several characteristics with human disease that could make dogs a more relevant preclinical model. Canine melanomas rarely arise in sun‐exposed sites. Most occur in the oral cavity, with a subset having intra‐epithelial malignant melanocytes mimicking the in situ component of human mucosal melanoma. The spectrum of canine melanocytic neoplasia includes benign lesions with some analogy to nevi, as well as invasive primary melanoma, and widespread metastasis. Growing evidence of distinct subtypes in humans, differing in somatic and predisposing germ‐line genetic alterations, cell of origin, epidemiology, relationship to ultraviolet radiation and progression from benign to malignant tumors, may also exist in dogs. Canine and human mucosal melanomas appear to harbor BRAF, NRAS, and c‐kit mutations uncommonly, compared with human cutaneous melanomas, although both species share AKT and MAPK signaling activation. We conclude that there is significant overlap in the clinical and histopathological features of canine and human mucosal melanomas. This represents opportunity to explore canine oral cavity melanoma as a preclinical model.

Prognostic assessment of hypoxia and metabolic markers in cervical cancer using automated digital image analysis of immunohistochemistry

BackgroundHypoxia inducible factor-1 alpha (HIF-1α), induced by tumor hypoxia, regulates tumor cell metabolism and metastasis by up-regulation of c-Met, carbonic anhydrase 9 (CA9) and glucose transporter 1 (GLUT1). The prognostic significance of hypoxia and metabolic markers is not clearly defined in cervical cancer. Here, we have examined the primary players in the hypoxia signaling pathway, by immunohistochemistry, but confirming their interactions, as well as defining which proteins are associated with outcome.MethodsThe study subjects were comprised of cervical intraepithelial neoplasia (CIN, n = 209), carcinoma in situ (CIS, n = 74), cervical cancer (n = 179), and matched nonadjacent normal tissues (n = 357). Immunohistochemistry (IHC) was performed to identify HIF-1α, c-Met, CA9, and GLUT1. IHC scoring was performed using automated digital image analysis and the association of hypoxic markers with prognostic outcome was evaluated.ResultsHIF-1α, c-Met, CA9 and GLUT1 expression were higher in cervical cancer than in CIN and normal cervix (all P < 0.001). Among these markers, expression of HIF-1α and c-Met were significantly different in FIGO stage (P < 0.001 and P = 0.019, respectively) and patients with lymph node metastasis (P < 0.001 and P = 0.010, respectively). HIF-1α expression was correlated with c-Met expression in cervical cancer (P < 0.001). High expression of HIF-1α and c-Met showed worse 5-year overall survival rate (P = 0.047 and P = 0.005, respectively) than low expression group, but CA9 and GLUT1 did not show significant survival difference. After adjusting the prognostic covariates, c-Met was found to be an independent risk factor (HR=3.27; 95% CI, 1.05-10.23, P = 0.041) for overall survival in cervical cancer.ConclusionsWe demonstrate that c-Met correlates with HIF-1α and is a poor prognostic factor in survival in cervical cancer.

Profiling of phospho-AKT, phospho-mTOR, phospho-MAPK and EGFR in non-small cell lung cancer.

Activation of numerous pathways has been documented in non-small cell lung cancer (NSCLC). Epidermal growth factor receptor (EGFR) has emerged as a common therapeutic target. The mitogen-activated protein kinase (MAPK) and AKT signaling pathways are downstream of EGFR and deregulated via genetic and epigenetic mechanisms in many human cancers. We evaluated selected markers in the EGFR pathway with reference to outcome. Tissues from 220 cases of NSCLC patients presented in a tissue microarray were assayed with immunohistochemistry for phosphorylated AKT, phosphorylated MAPK, phosphorylated mTOR, and EGFR and then quantified by automated image analysis. Individually, the biomarkers did not predict. Combined as ratios, p-mTOR/p-AKT, and p-MAPK/EGFR function as prognostic markers of survival (p=0.008 and p=0.029, respectively), however, no significance was found after adjustment (p=0.221, p=0.103). The sum of these ratios demonstrates a stronger correlation with survival (p<0.001) and remained statistically significant after adjustment (p=0.026). The algebraic combination of biomarkers offer the capacity to understand factors that predict outcome better than current approaches of evaluating biomarkers individually or in pairs. Our results show the sum of p-mTOR/p-AKT and p-MAPK/EGFR is a potential predictive marker of survival in NSCLC patients.

The Application of Digital Pathology to Improve Accuracy in Glomerular Enumeration in Renal Biopsies.

Background In renal biopsy reporting, quantitative measurements, such as glomerular number and percentage of globally sclerotic glomeruli, is central to diagnostic accuracy and prognosis. The aim of this study is to determine the number of glomeruli and percent globally sclerotic in renal biopsies by means of registration of serial tissue sections and manual enumeration, compared to the numbers in pathology reports from routine light microscopic assessment. Design We reviewed 277 biopsies from the Nephrotic Syndrome Study Network (NEPTUNE) digital pathology repository, enumerating 9,379 glomeruli by means of whole slide imaging. Glomerular number and the percentage of globally sclerotic glomeruli are values routinely recorded in the official renal biopsy pathology report from the 25 participating centers. Two general trends in reporting were noted: total number per biopsy or average number per level/section. Both of these approaches were assessed for their accuracy in comparison to the analogous numbers of annotated glomeruli on WSI. Results The number of glomeruli annotated was consistently higher than those reported (p<0.001); this difference was proportional to the number of glomeruli. In contrast, percent globally sclerotic were similar when calculated on total glomeruli, but greater in FSGS when calculated on average number of glomeruli (p<0.01). The difference in percent globally sclerotic between annotated and those recorded in pathology reports was significant when global sclerosis is greater than 40%. Conclusions Although glass slides were not available for direct comparison to whole slide image annotation, this study indicates that routine manual light microscopy assessment of number of glomeruli is inaccurate, and the magnitude of this error is proportional to the total number of glomeruli.

PLCE1 mRNA and protein expression and survival of patients with esophageal squamous cell carcinoma and gastric adenocarcinoma

Background: Germline genetic variants in PLCE1 (10q23) have demonstrated consistent associations with risk of esophageal squamous cell carcinoma (ESCC) and gastric cancer among Chinese. We evaluated PLCE1 mRNA and protein expression in paired tumor-normal tissues, and their relationship with survival. Methods: PLCE1 mRNA was profiled using three probes in the Affymetrix GeneChip U133 for paired tumor-normal tissues of ESCC (n = 132), gastric cardia adenocarcinoma (GCA, n = 62), and gastric noncardia adenocarcinoma (GNCA, n = 72). We used immunohistochemistry to detect PLCE1 protein on slides from tissue microarrays in paired tumor-normal tissues of ESCC (n = 303), and tumors of GCA (n = 298) and GNCA (n = 124). Results: Compared with normal tissues, PLCE1 mRNA expression was significantly reduced in ESCC tumors (P = 0.03, probe_205112_at), as well as in GCA and GNCA tumors (P < 0.0001, each probe). Protein expression was nonsignificantly reduced in ESCC tumors (P = 0.51). Increased tumor-normal mRNA fold change (probe_205112_at) was associated with longer survival in ESCC (9.6 months for highest vs. lowest quartile; Ptrend = 0.02). Increased mRNA tumor-normal fold change (probe_205111_at) was associated with longer survival for GCA (10.7 months for highest quartile; Ptrend = 0.04), but not for GNCA cases (P = 0.72). Similar to mRNA, elevated tumor-normal fold change for protein in ESCC was also associated with improved survival (8.1 months for highest quartile; Ptrend = 0.04). Conclusions: Dysregulated PLCE1 mRNA expression was observed for both ESCC (one probe only) and GCA tumors, and the altered PLCE1 expression seems to be associated with cancer prognosis. Impact: A potential role for PLCE1 in the early detection and/or therapy of ESCC and GCA warrants further investigation. Cancer Epidemiol Biomarkers Prev; 23(8); 1579–88. ©2014 AACR.

Observer Performance in the Use of Digital and Optical Microscopy for the Interpretation of Tissue-Based Biomarkers

Background. We conducted a validation study of digital pathology for the quantitative assessment of tissue-based biomarkers with immunohistochemistry. Objective. To examine observer agreement as a function of viewing modality (digital versus optical microscopy), whole slide versus tissue microarray (TMA) review, biomarker type (HER2 incorporating membranous staining and Ki-67 with nuclear staining), and data type (continuous and categorical). Methods. Eight pathologists reviewed 50 breast cancer whole slides (25 stained with HER2 and 25 with Ki-67) and 2 TMAs (1 stained with HER2, 1 with Ki-67, each containing 97 cores), using digital and optical microscopy. Results. Results showed relatively high overall interobserver and intermodality agreement, with different patterns specific to biomarker type. For HER2, there was better interobserver agreement for optical compared to digital microscopy for whole slides as well as better interobserver and intermodality agreement for TMAs. For Ki-67, those patterns were not observed. Conclusions. The differences in agreement patterns when examining different biomarkers and different scoring methods and reviewing whole slides compared to TMA stress the need for validation studies focused on specific pathology tasks to eliminate sources of variability that might dilute findings. The statistical uncertainty observed in our analyses calls for adequate sampling for each individual task rather than pooling cases.

Reproducibility in the automated quantitative assessment of HER2/neu for breast cancer

Background: With the emerging role of digital imaging in pathology and the application of automated image-based algorithms to a number of quantitative tasks, there is a need to examine factors that may affect the reproducibility of results. These factors include the imaging properties of whole slide imaging (WSI) systems and their effect on the performance of quantitative tools. This manuscript examines inter-scanner and inter-algorithm variability in the assessment of the commonly used HER2/neu tissue-based biomarker for breast cancer with emphasis on the effect of algorithm training. Materials and Methods: A total of 241 regions of interest from 64 breast cancer tissue glass slides were scanned using three different whole-slide images and were analyzed using two different automated image analysis algorithms, one with preset parameters and another incorporating a procedure for objective parameter optimization. Ground truth from a panel of seven pathologists was available from a previous study. Agreement analysis was used to compare the resulting HER2/neu scores. Results: The results of our study showed that inter-scanner agreement in the assessment of HER2/neu for breast cancer in selected fields of view when analyzed with any of the two algorithms examined in this study was equal or better than the inter-observer agreement previously reported on the same set of data. Results also showed that discrepancies observed between algorithm results on data from different scanners were significantly reduced when the alternative algorithm that incorporated an objective re-training procedure was used, compared to the commercial algorithm with preset parameters. Conclusion: Our study supports the use of objective procedures for algorithm training to account for differences in image properties between WSI systems.

Brightfield proximity ligation assay reveals both canonical and mixed transforming growth factor-β/bone morphogenetic protein Smad signaling complexes in tissue sections.

Transforming growth factor-β (TGF-β) is an important regulator of cellular homeostasis and disease pathogenesis. Canonical TGF-β signaling occurs through Smad2/3–Smad4 complexes; however, recent in vitro studies suggest that elevated levels of TGF-β may activate a novel mixed Smad complex (Smad2/3-Smad1/5/9), which is required for some of the pro-oncogenic activities of TGF-β. To determine if mixed Smad complexes are evident in vivo, we developed antibodies that can be used with a proximity ligation assay to detect either canonical or mixed Smad complexes in formalin-fixed paraffin-embedded sections. We demonstrate high expression of mixed Smad complexes in the tissues from mice genetically engineered to express high levels of TGF-β1. Mixed Smad complexes were also prominent in 15–16 day gestation mouse embryos and in breast cancer xenografts, suggesting important roles in embryonic development and tumorigenesis. In contrast, mixed Smad complexes were expressed at extremely low levels in normal adult mouse tissue, where canonical complexes were correspondingly higher. We show that this methodology can be used in archival patient samples and tissue microarrays, and we have developed an algorithm to quantitate the brightfield read-out. These methods will allow quantitative analysis of cell type-specific Smad signaling pathways in physiological and pathological processes.

Morphometry Predicts Early GFR Change in Primary Proteinuric Glomerulopathies: A Longitudinal Cohort Study Using Generalized Estimating Equations.

Objective Most predictive models of kidney disease progression have not incorporated structural data. If structural variables have been used in models, they have generally been only semi-quantitative. Methods We examined the predictive utility of quantitative structural parameters measured on the digital images of baseline kidney biopsies from the NEPTUNE study of primary proteinuric glomerulopathies. These variables were included in longitudinal statistical models predicting the change in estimated glomerular filtration rate (eGFR) over up to 55 months of follow-up. Results The participants were fifty-six pediatric and adult subjects from the NEPTUNE longitudinal cohort study who had measurements made on their digital biopsy images; 25% were African-American, 70% were male and 39% were children; 25 had focal segmental glomerular sclerosis, 19 had minimal change disease, and 12 had membranous nephropathy. We considered four different sets of candidate predictors, each including four quantitative structural variables (for example, mean glomerular tuft area, cortical density of patent glomeruli and two of the principal components from the correlation matrix of six fractional cortical areas–interstitium, atrophic tubule, intact tubule, blood vessel, sclerotic glomerulus, and patent glomerulus) along with 13 potentially confounding demographic and clinical variables (such as race, age, diagnosis, and baseline eGFR, quantitative proteinuria and BMI). We used longitudinal linear models based on these 17 variables to predict the change in eGFR over up to 55 months. All 4 models had a leave-one-out cross-validated R2 of about 62%. Conclusions Several combinations of quantitative structural variables were significantly and strongly associated with changes in eGFR. The structural variables were generally stronger than any of the confounding variables, other than baseline eGFR. Our findings suggest that quantitative assessment of diagnostic renal biopsies may play a role in estimating the baseline risk of succeeding loss of renal function in future clinical studies, and possibly in clinical practice.

Evaluation environment for digital and analog pathology: a platform for validation studies

Abstract. We present a platform for designing and executing studies that compare pathologists interpreting histopathology of whole slide images (WSIs) on a computer display to pathologists interpreting glass slides on an optical microscope. eeDAP is an evaluation environment for digital and analog pathology. The key element in eeDAP is the registration of the WSI to the glass slide. Registration is accomplished through computer control of the microscope stage and a camera mounted on the microscope that acquires real-time images of the microscope field of view (FOV). Registration allows for the evaluation of the same regions of interest (ROIs) in both domains. This can reduce or eliminate disagreements that arise from pathologists interpreting different areas and focuses on the comparison of image quality. We reduced the pathologist interpretation area from an entire glass slide (10 to 30  mm2) to small ROIs (<50  μm2). We also made possible the evaluation of individual cells. We summarize eeDAP’s software and hardware and provide calculations and corresponding images of the microscope FOV and the ROIs extracted from the WSIs. The eeDAP software can be downloaded from the Google code website (project: eeDAP) as a MATLAB source or as a precompiled stand-alone license-free application.