Unusual Presentation of Widely Metastatic Extraskeletal Osteosarcoma: Case Report

Extraskeletal osteosarcoma is a highly aggressive malignant osteoid forming mesenchymal neoplasm arising from soft tissues which accounts for 1% of all soft tissue sarcomas. We report the case of a 46-year-old female with no significant past medical history presenting to an emergency department with a right lateral thigh mass following minor trauma. She was eventually found to have high grade extraskeletal osteosarcoma with rapid progression of disease resulting in patient demise. Differentiation of these lesions from alternative processes relies on specific imaging and pathologic features. Differential diagnoses include both benign and malignant etiologies such as myositis ossificans, soft tissue hemangiomas, and other malignant soft tissue neoplasms such as epithelial and synovial sarcoma.

Deep-learning and MR images to target hypoxic habitats with evofosfamide in preclinical models of sarcoma

Rationale: Hypoxic regions (habitats) within tumors are heterogeneously distributed and can be widely variant. Hypoxic habitats are generally pan-therapy resistant. For this reason, hypoxia-activated prodrugs (HAPs) have been developed to target these resistant volumes. The HAP evofosfamide (TH-302) has shown promise in preclinical and early clinical trials of sarcoma. However, in a phase III clinical trial of non-resectable soft tissue sarcomas, TH-302 did not improve survival in combination with doxorubicin (Dox), possibly due to a lack of patient stratification based on hypoxic status. Therefore, we used magnetic resonance imaging (MRI) to identify hypoxic habitats and non-invasively follow therapies response in sarcoma mouse models. Methods: We developed deep-learning (DL) models to identify hypoxia, using multiparametric MRI and co-registered histology, and monitored response to TH-302 in a patient-derived xenograft (PDX) of rhabdomyosarcoma and a syngeneic model of fibrosarcoma (radiation-induced fibrosarcoma, RIF-1). Results: A DL convolutional neural network showed strong correlations (>0.76) between the true hypoxia fraction in histology and the predicted hypoxia fraction in multiparametric MRI. TH-302 monotherapy or in combination with Dox delayed tumor growth and increased survival in the hypoxic PDX model (p<0.05), but not in the RIF-1 model, which had a lower volume of hypoxic habitats. Control studies showed that RIF-1 resistance was due to hypoxia and not other causes. Notably, PDX tumors developed resistance to TH-302 under prolonged treatment that was not due to a reduction in hypoxic volumes. Conclusion: Artificial intelligence analysis of pre-therapy MR images can predict hypoxia and subsequent response to HAPs. This approach can be used to monitor therapy response and adapt schedules to forestall the emergence of resistance.

Spontaneous cell fusions as a mechanism of parasexual recombination in tumour cell populations

The initiation and progression of cancers reflect the underlying process of somatic evolution, in which the diversification of heritable phenotypes provides a substrate for natural selection, resulting in the outgrowth of the most fit subpopulations. Although somatic evolution can tap into multiple sources of diversification, it is assumed to lack access to (para)sexual recombination-a key diversification mechanism throughout all strata of life. On the basis of observations of spontaneous fusions involving cancer cells, the reported genetic instability of polypoid cells and the precedence of fusion-mediated parasexual recombination in fungi, we asked whether cell fusions between genetically distinct cancer cells could produce parasexual recombination. Using differentially labelled tumour cells, we found evidence of low-frequency, spontaneous cell fusions between carcinoma cells in multiple cell line models of breast cancer both in vitro and in vivo. While some hybrids remained polyploid, many displayed partial ploidy reduction, generating diverse progeny with heterogeneous inheritance of parental alleles, indicative of partial recombination. Hybrid cells also displayed elevated levels of phenotypic plasticity, which may further amplify the impact of cell fusions on the diversification of phenotypic traits. Using mathematical modelling, we demonstrated that the observed rates of spontaneous somatic cell fusions may enable populations of tumour cells to amplify clonal heterogeneity, thus facilitating the exploration of larger areas of the adaptive landscape (relative to strictly asexual populations), which may substantially accelerate a tumour's ability to adapt to new selective pressures.

Artificial selection for host resistance to tumour growth and subsequent cancer cell adaptations: an evolutionary arms race

BACKGROUND

Cancer progression is governed by evolutionary dynamics in both the tumour population and its host. Since cancers die with the host, each new population of cancer cells must reinvent strategies to overcome the host's heritable defences. In contrast, host species evolve defence strategies over generations if tumour development limits procreation.

METHODS

We investigate this "evolutionary arms race" through intentional breeding of immunodeficient SCID and immunocompetent Black/6 mice to evolve increased tumour suppression. Over 10 generations, we injected Lewis lung mouse carcinoma cells [LL/2-Luc-M38] and selectively bred the two individuals with the slowest tumour growth at day 11. Their male progeny were hosts in the subsequent round.

RESULTS

The evolved SCID mice suppressed tumour growth through biomechanical restriction from increased mesenchymal proliferation, and the evolved Black/6 mice suppressed tumour growth by increasing immune-mediated killing of cancer cells. However, transcriptomic changes of multicellular tissue organisation and function genes allowed LL/2-Luc-M38 cells to adapt through increased matrix remodelling in SCID mice, and reduced angiogenesis, increased energy utilisation and accelerated proliferation in Black/6 mice.

CONCLUSION

Host species can rapidly evolve both immunologic and non-immunologic tumour defences. However, cancer cell plasticity allows effective phenotypic and population-based counter strategies.

NCCN Guidelines Insights: Soft Tissue Sarcoma, Version 1.2021

The NCCN Guidelines for Soft Tissue Sarcoma provide recommendations for the diagnosis, evaluation, treatment, and follow-up for patients with soft tissue sarcomas. These NCCN Guidelines Insights summarize the panel discussion behind recent important updates to the guidelines, including the development of a separate and distinct guideline for gastrointestinal stromal tumors (GISTs); reconception of the management of desmoid tumors; inclusion of further recommendations for the diagnosis and management of extremity/body wall, head/neck sarcomas, and retroperitoneal sarcomas; modification and addition of systemic therapy regimens for sarcoma subtypes; and revision of the principles of radiation therapy for soft tissue sarcomas.

H3F3A G34 mutation DNA sequencing and G34W immunohistochemistry analysis in 366 cases of giant cell tumors of bone and other bone tumors

H3F3A mutations and the expression of glycine 34 to tryptophan (G34W) mutants in giant cell tumors of bone (GCTBs) and other bone tumors were detected to compare H3F3A mutation types and the expression of G34W-mutant protein in order to provide a theoretical basis for using H3F3A mutations as a diagnostic and differential-diagnostic tool for GCTBs. A total of 366 bone tumor cases were investigated. The cases involved 215 men and 151 women, whose median age was 29 years (3-84). The cases included GCTB (n=180), recurrent GCTB (n=19), GCTB with lung metastasis (n=5), pediatric GCTB (n=15), primary malignant GCTB (n=5), chondroblastoma (CB, n=61), chondrosarcoma grade II (n=15), dedifferentiated chondrosarcoma (n=17), chondromyxoid fibroma (n=9), aneurysmal bone cyst (n=9), nonossifying fibroma (n=9), osteosarcoma (n=16), and undifferentiated sarcoma (n=6). Sanger DNA sequencing analysis was used to detect H3F3A mutations. Immunohistochemistry was used to assess the expression of the G34W-mutated protein in these bone tumors. DNA sequencing results revealed H3F3A mutations in 95.00% of GCTBs (171/180), including glycine 34 to tryptophan (G34W, 163/180, 90.56%), glycine 34 to leucine (G34L, 3/180, 1.67%), glycine 34 to valine (G34V, 3/180, 1.67%), and glycine 34 to arginine (G34R, 2/180, 1.11%). Recurrent GCTBs mostly had the H3F3A G34W mutation (18/19, 94.74%), and GCTBs with lung metastasis all had the H3F3A G34W mutation (5/5, 100%). Pediatric GCTBs had a mutation rate of 93.33% (14/15), including one case with G34L. Four cases of primary malignant GCTB showed the H3F3A G34W mutation (4/5, 80.00%), and the classical GCTB component and malignant component showed consistent mutation types. Immunohistochemistry showed that GCTBs harboring G34W also expressed the mutant protein in tumor cell nuclei. Furthermore, one case of GCTB and one case of recurrent GCTB showed positive G34W immunostaining results despite being negative for the genetic mutation. Other bone tumors all showed wild-type expression in both DNA sequencing and immunohistochemistry. Our large-sample DNA sequencing analysis detected four different forms of mutations in GCTBs, including three rare mutation forms. The most common mutation of H3F3A was G34W, which was in accordance with the expression of G34W in GCTBs detected by immunohistochemistry. Although DNA sequencing analysis detected rare mutation types of H3F3A, false-negative results were also present due to the small number of cells in the samples. Detection of the most common (G34W) mutant protein by immunohistochemistry was more convenient. Given the high prevalence of these driver mutations, the detection of H3F3A mutant proteins can assist in the diagnosis of GCTB and its differential diagnosis from other bone tumors.

Soft Tissue Sarcoma, Version 2.2018, NCCN Clinical Practice Guidelines in Oncology

Soft tissue sarcomas (STS) are rare solid tumors of mesenchymal cell origin that display a heterogenous mix of clinical and pathologic characteristics. STS can develop from fat, muscle, nerves, blood vessels, and other connective tissues. The evaluation and treatment of patients with STS requires a multidisciplinary team with demonstrated expertise in the management of these tumors. The complete NCCN Guidelines for STS provide recommendations for the diagnosis, evaluation, and treatment of extremity/superficial trunk/head and neck STS, as well as intra-abdominal/retroperitoneal STS, gastrointestinal stromal tumors, desmoid tumors, and rhabdomyosarcoma. This portion of the NCCN Guidelines discusses general principles for the diagnosis, staging, and treatment of STS of the extremities, superficial trunk, or head and neck; outlines treatment recommendations by disease stage; and reviews the evidence to support the guidelines recommendations.

Clinical, pathological, and genomic features of EWSR1-PATZ1 fusion sarcoma

Molecular diagnostics of sarcoma subtypes commonly involve the identification of characteristic oncogenic fusions. EWSR1-PATZ1 is a rare fusion partnering in sarcoma, with few cases reported in the literature. In the current study, a series of 11 cases of EWSR1-PATZ1 fusion positive malignancies are described. EWSR1-PATZ1-related sarcomas occur across a wide age range and have a strong predilection for chest wall primary site. Secondary driver mutations in cell-cycle genes, and in particular CDKN2A (71%), are common in EWSR1-PATZ1 sarcomas in this series. In a subset of cases, an extended clinical and histopathological review was performed, as was confirmation and characterization of the fusion breakpoint revealing a novel intronic pseudoexon sequence insertion. Unified by a shared gene fusion, EWSR1-PATZ1 sarcomas otherwise appear to exhibit divergent morphology, a polyphenotypic immunoprofile, and variable clinical behavior posing challenges for precise classification.

Quantitative Image Analysis of Human Epidermal Growth Factor Receptor 2 Immunohistochemistry for Breast Cancer: Guideline From the College of American Pathologists

CONTEXT.—

Advancements in genomic, computing, and imaging technology have spurred new opportunities to use quantitative image analysis (QIA) for diagnostic testing.

OBJECTIVE.—

To develop evidence-based recommendations to improve accuracy, precision, and reproducibility in the interpretation of human epidermal growth factor receptor 2 (HER2) immunohistochemistry (IHC) for breast cancer where QIA is used.

DESIGN.—

The College of American Pathologists (CAP) convened a panel of pathologists, histotechnologists, and computer scientists with expertise in image analysis, immunohistochemistry, quality management, and breast pathology to develop recommendations for QIA of HER2 IHC in breast cancer. A systematic review of the literature was conducted to address 5 key questions. Final recommendations were derived from strength of evidence, open comment feedback, expert panel consensus, and advisory panel review.

RESULTS.—

Eleven recommendations were drafted: 7 based on CAP laboratory accreditation requirements and 4 based on expert consensus opinions. A 3-week open comment period received 180 comments from more than 150 participants.

CONCLUSIONS.—

To improve accurate, precise, and reproducible interpretation of HER2 IHC results for breast cancer, QIA and procedures must be validated before implementation, followed by regular maintenance and ongoing evaluation of quality control and quality assurance. HER2 QIA performance, interpretation, and reporting should be supervised by pathologists with expertise in QIA.

Leiomyosarcoma of the Inferior Vena Cava with Hepatic and Pulmonary Metastases: Case Report

Sarcomas are connective tissue tumors accounting for only 1% of all adult malignancies. Leiomyosarcoma (LMS) is a sarcoma arising from smooth muscle cells, and accounts for 10-20% of all sarcomas. A subtype of LMS are those originating from the smooth muscle of blood vessels. Leiomyosarcoma of the inferior vena cava is a sarcomatous tumor, with less than 350 cases described in the literature. It carries a poor prognosis, with 5- and 10-year survival rates of 31.4% and 7.4%, respectively. We present a case of a 46-year-old female with no significant past medical history presented to the emergency department with mild abdominal pain and distention, early satiety, and weight loss for three weeks, found to have unresectable metastatic leiomyosarcoma of the inferior vena cava.

Computational pathology definitions, best practices, and recommendations for regulatory guidance: a white paper from the Digital Pathology Association

In this white paper, experts from the Digital Pathology Association (DPA) define terminology and concepts in the emerging field of computational pathology, with a focus on its application to histology images analyzed together with their associated patient data to extract information. This review offers a historical perspective and describes the potential clinical benefits from research and applications in this field, as well as significant obstacles to adoption. Best practices for implementing computational pathology workflows are presented. These include infrastructure considerations, acquisition of training data, quality assessments, as well as regulatory, ethical, and cyber-security concerns. Recommendations are provided for regulators, vendors, and computational pathology practitioners in order to facilitate progress in the field. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Validation of Fluorescence in situ Hybridization Testing of USP6 Gene Rearrangement for Diagnosis of Primary Aneurysmal Bone Cyst

GOALS

Ubiquitin specific protease 6 (USP6) gene rearrangement has been reported in approximately 70%-75% of aneurysmal bone cyst cases. We hypothesize that fluorescence in situ hybridization (FISH) testing of this marker will be useful in the pathological differentiation of primary aneurysmal bone cyst (ABC), secondary ABC, giant cell tumor of bone (GCT), and telangiectatic osteosarcoma (TOS) which are morphologically similar. This study aims to evaluate the efficacy of this test and validate it for diagnostic use.

PROCEDURES

FISH was performed in primary ABC, secondary ABC, GCT and TOS using dual color USP6 gene break apart probes. The sensitivity, specificity, positive predictive value, and negative predictive values were calculated.

RESULTS

Primary ABC demonstrates USP6 rearrangement. All secondary ABC, GCT and TOS were negative. The test sensitivity and specificity in primary ABC were 53% (9/17) and 100% (18/18), respectively. The positive predictive value and negative predictive value were 100% (9/9) and 69% (18/26), respectively.

CONCLUSION

The USP6 gene break apart detected by FISH is validated as a novel diagnostic tool for primary ABC in our laboratory. This test could be used to study the predictive value of USP6 targeted therapy for primary ABC in the near future.

Multiparametric MRI and Coregistered Histology Identify Tumor Habitats in Breast Cancer Mouse Models

It is well-recognized that solid tumors are genomically, anatomically, and physiologically heterogeneous. In general, more heterogeneous tumors have poorer outcomes, likely due to the increased probability of harboring therapy-resistant cells and regions. It is hypothesized that the genomic and physiologic heterogeneity are related, because physiologically distinct regions will exert variable selection pressures leading to the outgrowth of clones with variable genomic/proteomic profiles. To investigate this, methods must be in place to interrogate and define, at the microscopic scale, the cytotypes that exist within physiologically distinct subregions ("habitats") that are present at mesoscopic scales. MRI provides a noninvasive approach to interrogate physiologically distinct local environments, due to the biophysical principles that govern MRI signal generation. Here, we interrogate different physiologic parameters, such as perfusion, cell density, and edema, using multiparametric MRI (mpMRI). Signals from six different acquisition schema were combined voxel-by-voxel into four clusters identified using a Gaussian mixture model. These were compared with histologic and IHC characterizations of sections that were coregistered using MRI-guided 3D printed tumor molds. Specifically, we identified a specific set of MRI parameters to classify viable-normoxic, viable-hypoxic, nonviable-hypoxic, and nonviable-normoxic tissue types within orthotopic 4T1 and MDA-MB-231 breast tumors. This is the first coregistered study to show that mpMRI can be used to define physiologically distinct tumor habitats within breast tumor models. SIGNIFICANCE: This study demonstrates that noninvasive imaging metrics can be used to distinguish subregions within heterogeneous tumors with histopathologic correlation.

ADAM10 Is a Potential Novel Prognostic Biomarker for Sacral Chordoma

The ADAM (A Disintegrin and Metalloprotease) is a zinc-dependent family of transmembrane proteins upregulated in cancers. As the most frequent member, ADAM10's potential prognostic role in chordoma is unknown.

OBJECTIVE

We investigated the expression of ADAM10 protein and its prognostic value in sacral chordoma.

DESIGN

Clinical information of patients with sacral chordoma diagnosis during a 7-year period and their archived pathology were retrieved. Immunohistochemistry study of the expression of ADAM10 protein in sacral chordoma and control samples was conducted. The ADAM10 expression was correlated with the patients' clinicopathological information and analyzed by statistical methods.

RESULTS

The average age of 64 patients was 57.6 years (range, 35-83 years). Follow-up ranged from 12 to 141 months (mean, 72 months). The histological type included 47 classic, 6 chondroid, and 11 dedifferentiated chordomas. The expression level of ADAM10 was significantly correlated with the histological type (χ ²=11.345, P=0.003), metastasis (χ ²=10.149, P=0.001), overall survival (log-rank test: χ ²=8.177, P=0.004) and disease free survival (log-rank test: χ ²=6.805, P=0.009). The average survival time of patients with weak expression of ADAM10 was longer than that of strong expression.

CONCLUSION

The expression of ADAM10 protein is related to the histologic type and the prognosis of sacral chordoma.

Introduction to Digital Image Analysis in Whole-slide Imaging: A White Paper from the Digital Pathology Association

The advent of whole-slide imaging in digital pathology has brought about the advancement of computer-aided examination of tissue via digital image analysis. Digitized slides can now be easily annotated and analyzed via a variety of algorithms. This study reviews the fundamentals of tissue image analysis and aims to provide pathologists with basic information regarding the features, applications, and general workflow of these new tools. The review gives an overview of the basic categories of software solutions available, potential analysis strategies, technical considerations, and general algorithm readouts. Advantages and limitations of tissue image analysis are discussed, and emerging concepts, such as artificial intelligence and machine learning, are introduced. Finally, examples of how digital image analysis tools are currently being used in diagnostic laboratories, translational research, and drug development are discussed.

Phosphaturic mesenchymal tumor with an admixture of epithelial and mesenchymal elements in the jaws: clinicopathological and immunohistochemical analysis of 22 cases with literature review

Information on the heterogeneity of phosphaturic mesenchymal tumor, a rare entity associated with tumor-induced osteomalacia, is limited. In this retrospective analysis of 222 phosphaturic mesenchymal tumors, 22 cases exhibited mixed mesenchymal and epithelial elements, which we propose to term "phosphaturic mesenchymal tumor, mixed epithelial, and connective tissue type." Phosphaturic mesenchymal tumor of the mixed epithelial and connective tissue type showed a distinctive and significant male predominance (male:female = 2.67:1), with most patients diagnosed at <40 years old. Moreover, all tumors were mainly located in the alveolar bone with focal invasion into surrounding soft tissue and oral mucosa, which could be detected preoperatively by oral examination. The mesenchymal component, composed of spindled cells resembling fibroblasts or myofibroblasts arranged in a storiform or fascicular pattern, exhibited a less prominent vasculature and lower cellularity than the typical phosphaturic mesenchymal tumor (mixed connective tissue type). The epithelial component was typically haphazardly and diffusely distributed throughout the tumor, forming small, irregular nests resembling odontogenic epithelial nests. All cases were immunoreactive for fibroblast growth factor-23, somatostatin receptor 2A, and NSE in both components. Mostly also demonstrated positive staining for CD99 (21/22, 96%), CD56 (16/22, 73%), Bcl-2 (21/22, 96%), and D2-40 (19/22, 86%) in one or both components. S100 was positive in both components in one of seven cases. Interestingly, immunoreactivity was typically stronger and more diffuse in the epithelial than in the paired mesenchymal components. The mesenchymal component was also diffusely positive for CD68 (17/17, 100%) and showed variable focal staining for SMA (15/22, 68%) and CD34 (9/19, 47 %). These results indicate that phosphaturic mesenchymal tumor of the mixed epithelial and connective tissue type has distinctive clinicopathological characteristics and a polyimmunophenotypic profile.

Clinical Utility of Genomic Profiling in the Treatment of Advanced Sarcomas: A Single-Center Experience

Purpose

Sarcomas are a diverse group of malignant tumors that arise from soft tissues or bone. For most advanced cases, there is a substantial need for improved therapeutic options and, therefore, a desire to more precisely tailor therapy in individual cases. In this study, we review our institutional experience with next-generation sequencing (NGS)–based molecular profiling for non–GI stromal tumors sarcomas, with a focus on the clinical utility of the results.

Patients and Methods

We retrospectively analyzed results of NGS performed on tumors from 114 patients with a diagnosis of sarcoma. A chart review was conducted to review the clinical impact of NGS findings.

Results

A median of three putatively oncogenic gene alterations were identified per tumor sample (range, 0 to 19) and at least one mutation was detected in 96.7% of tumors. Fifty-six patients (49.1%) harbored a finding that was felt to be actionable after review by a molecular tumor board. Five patients (4.4%) had a diagnosis change as a result of NGS findings. In 15 patients (13.2%), therapeutic selection was influenced by NGS findings. Four of 15 (26.7%) of the NGS-influenced systemic therapies resulted in clinical benefit.

Conclusion

Putatively oncogenic mutations are readily detected in the majority of sarcomas. Genetic profiling affected the diagnosis and/or treatment approach in a sizeable minority of patients with sarcoma treated at our center. Additional study is required to determine if genetic profiling leads to improved clinical outcomes.

Abstract 2395: Acid-induced autophagic protein products are stored as adiposomes in breast cancer cells

Malignant tumors exhibit altered metabolism and consume higher levels of glucose compared to surrounding normal tissue, resulting in an acidic extracellular microenvironment. Adaptation to acidic conditions is a pre-requisite for tumor cells to survive and to out-compete the stroma into which they invade. Our previous studies demonstrated that acid adaptation is associated with survival mechanisms like chronic activation of autophagy and redistribution of the lysosomal proteins to the plasma membrane. When grown under acidic pH, breast cancer cells accumulate lipids as revealed by staining with Nile Red and perilipin 2, a protein that coats lipid droplets (adiposomes). Adiposomes are dynamic organelles that store neutral lipids surrounded by a shell of proteins and phospholipid monolayer. The lipids stored in adiposomes are produced de novo, as acid-induced lipogenic phenotype is maintained, even if cells are grown with de-lipidated serum. Fatty acid synthesis inhibition was selectively toxic under acidic conditions as compared to neutral pH and attenuated acid-induced adiposome accumulation. Using 13C isotopomer analysis, we observed a major shift in glucose metabolism from Embden Meyerhof to the Pentose Phosphate Pathway, resulting in increased production of NADPH, necessary for de novo lipid synthesis. To identify the carbon source of the lipid precursors in adiposomes, we employed 13C tracer analysis using [UL] 13C Glucose, 13C3 Leucine (labeled to steady-state) 13C2 Acetate and [UL] 13C glutamine as sources of lipids in the media. 13C label incorporation was determined by LC-MS/MS from adiposomes isolated from cells grown in media containing delipidated serum at pH 6.5. Label incorporation to glycerol backbone and acyl chains of lipids was observed when 13C glucose was used as the source. We could detect (M+1 ~6% of total) labeled 13C in triglycerides from adiposomes isolated from 13C3 leucine labeled MCF7, T47D and ZR75.1 cells. These data indicate that ketogenic amino acids arising from the autophagic breakdown of proteins are the major source of carbons in adiposomal lipids. Additionally, adiposome accumulation was significantly inhibited when cells were treated with autophagy inhibitors indicating that acid induced adiposomogenesis depends on autophagy. Further, we investigated the role of various acid-sensing GPCRs such as OGR1 and TDAG8 in transducing the acid signal. CRISPR/Cas9 mediated depletion of these receptors demonstrated that only OGR1 depletion abrogated acid induced adiposome accumulation and were defective in autophagy. In addition, acid-induced adiposomogenesis required PI3K and pAkt signaling. Hence, accumulation of adiposomes is a highly regulated metabolic process related to storing autophagic products, and appears to be important in cell survival under acidosis. This increased dependence on lipid metabolism reveals novel therapeutic vulnerabilities.

Citation Format: Smitha R. Pillai, Jonathan W. Wojtkowiak, Jonathan Nguyen, Mehdi Damaghi, Marilyn M. Bui, Timothy Garrett, Robert J. Gillies. Acid-induced autophagic protein products are stored as adiposomes in breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2395.

US Food and Drug Administration Approval of Whole Slide Imaging for Primary Diagnosis: A Key Milestone Is Reached and New Questions Are Raised

April 12, 2017 marked a significant day in the evolution of digital pathology in the United States, when the US Food and Drug Administration announced its approval of the Philips IntelliSite Pathology Solution for primary diagnosis in surgical pathology. Although this event is expected to facilitate more widespread adoption of whole slide imaging for clinical applications in the United States, it also raises a number of questions as to the means by which pathologists might choose to incorporate this technology into their clinical practice. This article from the College of American Pathologists Digital Pathology Committee reviews frequently asked questions on this topic and provides answers based on currently available information.

A phase-1/2 study of adenovirus-p53 transduced dendritic cell vaccine in combination with indoximod in metastatic solid tumors and invasive breast cancer

Background

Indoleamine 2, 3-dioxygenase is an enzyme that causes immunosuppression in tumors. Indoximod inhibits the indoleamine 2, 3-dioxygenase pathway and enhances immunologic responses to dendritic cell (DC) vaccines preclinically. Adenovirus p53 (Ad.p53) is used to generate DC vaccines against p53. A phase-1/2 trial of indoximod with Ad.p53-DC vaccine was conducted.

Materials and Methods

The phase-1 study combined 7 indoximod dose levels with < 6 Ad.p53-DC vaccinations every 2 weeks. Primary endpoints were maximum-tolerated dose in phase 1 and objective response in phase 2. Flow cytometry measured immune responses.

Results

Thirty-nine patients were treated. In combination with Ad.p53-DC vaccine, the maximum-tolerated dose of indoximod was 1600 mg twice daily. Attributable toxicities were grade 1–2. Best response was stable disease in 4 patients. Immunologic responses were detected in 7 out of 23 evaluable patients. Median progression-free survival was 13.3 weeks (95% confidence interval, 12.97–21.85) and median overall survival was 20.71 weeks (95% confidence interval, 25.75–46.15). Nine out of 22 patients (40%) benefitted from chemotherapy after vaccination. Median overall survival in chemotherapy responders was 69.4 weeks (30.1–122.1).

Conclusions

Indoximod 1600 mg twice daily with Ad.p53-DC was well tolerated. There may have been a chemosensitization effect. Future trials should explore combining this treatment with chemotherapy.

Soft Tissue Sarcoma, Version 2.2016, NCCN Clinical Practice Guidelines in Oncology

Soft tissue sarcomas (STS) are rare solid tumors of mesenchymal cell origin that display a heterogenous mix of clinical and pathologic characteristics. STS can develop from fat, muscle, nerves, blood vessels, and other connective tissues. The evaluation and treatment of patients with STS requires a multidisciplinary team with demonstrated expertise in the management of these tumors. The complete NCCN Guidelines for Soft Tissue Sarcoma (available at NCCN.org) provide recommendations for the diagnosis, evaluation, and treatment of extremity/superficial trunk/head and neck STS, as well as intra-abdominal/retroperitoneal STS, gastrointestinal stromal tumor, desmoid tumors, and rhabdomyosarcoma. This manuscript discusses guiding principles for the diagnosis and staging of STS and evidence for treatment modalities that include surgery, radiation, chemoradiation, chemotherapy, and targeted therapy.

Soft Tissue Tumor Immunohistochemistry Update: Illustrative Examples of Diagnostic Pearls to Avoid Pitfalls

CONTEXT

- Current 2013 World Health Organization classification of tumors of soft tissue arranges these tumors into 12 groups according to their histogenesis. Tumor behavior is classified as benign, intermediate (locally aggressive), intermediate (rarely metastasizing), and malignant. In our practice, a general approach to reaching a definitive diagnosis of soft tissue tumors is to first evaluate clinicoradiologic, histomorphologic, and cytomorphologic features of the tumor to generate some pertinent differential diagnoses. These include the potential line of histogenesis and whether the tumor is benign or malignant, and low or high grade. Although molecular/genetic testing is increasingly finding its applications in characterizing soft tissue tumors, currently immunohistochemistry still not only plays an indispensable role in defining tumor histogenesis, but also serves as a surrogate for underlining molecular/genetic alterations. Objective- To provide an overview focusing on the current concepts in the classification and diagnosis of soft tissue tumors, incorporating immunohistochemistry. This article uses examples to discuss how to use the traditional and new immunohistochemical markers for the diagnosis of soft tissue tumors. Practical diagnostic pearls, summary tables, and figures are used to show how to avoid diagnostic pitfalls.

DATA SOURCES

- Data were obtained from pertinent peer-reviewed English-language literature and the authors' first-hand experience as bone and soft tissue pathologists.

CONCLUSIONS

- -The ultimate goal for a pathologist is to render a specific diagnosis that provides diagnostic, prognostic, and therapeutic information to guide patient care. Immunohistochemistry is integral to the diagnosis and management of soft tissue tumors.