IRF4 translocation status in pediatric follicular and diffuse large B-cell lymphoma patients enrolled in Children's Oncology Group trials.

Large B-cell lymphoma with IRF4 rearrangement is a provisional entity in the 2017 World Health Organization classification. In order to characterize these lymphomas in children from the United States, IRF4 FISH and immunohistochemical stains were performed on 32 follicular lymphoma and diffuse large B-cell lymphoma (DLBCL) from Children's Oncology Group studies. Two DLBCLs (6%) had IRF4 rearrangements, one involving the ileocecal valve and another involving the tonsil and cerebrospinal fluid. Both cases had strong, diffuse IRF4/MUM1 immunohistochemical staining, which may be a pathologic clue to the diagnosis. Reclassification of these cases may have prognostic and therapeutic implications.

Laboratory-Developed Tests: A Legislative and Regulatory Review.

BACKGROUND: Twenty-five years ago, the Food and Drug Administration (FDA) asserted in a draft document that "home brew" tests-now commonly referred to as laboratory-developed tests (LDTs)-are subject to the same regulatory oversight as other in vitro diagnostics (IVDs)4. In 2010, the FDA began work on developing a proposed framework for future LDT oversight. Released in 2014, the draft guidance sparked an intense debate over potential LDT regulation. While the proposed guidance has not been implemented, many questions regarding LDT oversight remain unresolved. CONTENT: This review provides an overview of federal statutes and regulations related to IVDs and clinical laboratory operations, with a focus on those potentially applicable to LDTs and proposed regulatory efforts. Sources reviewed include the Code of Federal Regulations, the Federal Register, congressional hearings, guidance and policy documents, position statements, published literature, and websites. SUMMARY: Federal statutes regarding IVDs were passed without substantive evidence of congressional consideration toward the concept of LDTs. The FDA has clear oversight authority over IVD reagents introduced into interstate commerce. A 16-year delay in publicly asserting FDA authority over LDTs, the pursuit of a draft guidance approach toward oversight, and establishment of regulations under the Clinical Laboratory Improvement Amendments of 1988 (CLIA'88) applicable to LDTs contributed to community uncertainty toward LDT oversight. Future regulatory and/or legislative efforts may be required to resolve this uncertainty.

Cutaneous epithelioid osteoblastoma.

Epithelioid osteoblastomas (EOB) typically arise in the axial skeleton of young adults, but there are rare case reports of the lesion arising in soft tissue. To date, only 1 case has been reported in the skin, and it has been debated in the literature if that case was truly a neoplasm. With the availability of the new osteoblastic marker SAT2B, the authors present a case of an EOB with confirmed osteoblastic differentiation arising in the tattooed skin of a 32-year-old army veteran. Despite the rarity of the neoplasm, 2 other cases of soft tissue EOB are reported in the literature, also involving military servicemembers. The identification of this unique tumor solely in military personnel is likely due to the relatively high proportion of young males represented in the military, the demographic most likely to develop osteoblastomas. Less likely, the authors postulate the possible existence of an occupational risk factor for soft tissue EOB in military service.

Communicating Certainty in Pathology Reports.

CONTEXT.­: Pathology reports are the main modality in which results are communicated to other physicians. For various reasons, the diagnosis may be qualified on a spectrum of uncertainty. OBJECTIVE.­: To examine how communication of uncertainty is an unexamined source of possible medical error. No study to our knowledge has examined pathology reports across multiple institutions. This study seeks to identify commonly used phrases of diagnostic uncertainty and their interpreted meanings by surgical pathologists and clinicians. DESIGN.­: Anonymous surveys were completed at 3 major US academic institutions by 18 practicing staff pathologists, 12 pathology residents, 53 staff clinicians, and 50 resident/allied health professional clinicians at 5 standard tumor boards. All participants rated percentage certainty associated with 7 diagnostic terms. Pathologists answered 2 questions related to the ability to clarify a diagnosis using a comment and comfort wording pathology reports. Clinicians answered questions on how often they read a pathology report comment, if they found the comment helpful, and how comfortable they were in reading pathology reports. RESULTS.­: A wide range in percentage certainty was found for each of the 7 diagnostic phrases. Both staff and resident clinicians and residents showed wide variability in interpreting the phrases. Twenty-five of 50 staff clinicians (52%) were very comfortable reading a pathology report, whereas only 4 of 53 resident clinicians (8%) were very comfortable reading a pathology report. Twenty-four of 53 staff clinicians (63%) reported always reading the comment, yet only 20 of 53 (27%) always found the comment helpful. The phrases "diagnostic of" and "consistent with" had the strongest agreement in meaning. The weakest agreement was between "suspicious for" and "compatible with." CONCLUSIONS.­: Efforts to standardize diagnostic terms may improve communication.

Improving Augmented Human Intelligence to Distinguish Burkitt Lymphoma From Diffuse Large B-Cell Lymphoma Cases.

OBJECTIVES: To assess and improve the assistive role of a deep, densely connected convolutional neural network (CNN) to hematopathologists in differentiating histologic images of Burkitt lymphoma (BL) from diffuse large B-cell lymphoma (DLBCL). METHODS: A total of 10,818 images from BL (n = 34) and DLBCL (n = 36) cases were used to either train or apply different CNNs. Networks differed by number of training images and pixels of images, absence of color, pixel and staining augmentation, and depth of the network, among other parameters. RESULTS: Cases classified correctly were 17 of 18 (94%), nine with 100% of images correct by the best performing network showing a receiver operating characteristic curve analysis area under the curve 0.92 for both DLBCL and BL. The best performing CNN used all available training images, two random subcrops per image of 448 × 448 pixels, random H&E staining image augmentation, random horizontal flipping of images, random alteration of contrast, reduction on validation error plateau of 15 epochs, block size of six, batch size of 32, and depth of 22. Other networks and decreasing training images had poorer performance. CONCLUSIONS: CNNs are promising augmented human intelligence tools for differentiating a subset of BL and DLBCL cases.

Macrophage HIF-1α Is an Independent Prognostic Indicator in Kidney Cancer.

PURPOSE: Clear cell renal cell carcinoma (ccRCC) is frequently associated with inactivation of the von Hippel-Lindau tumor suppressor, resulting in activation of HIF-1α and HIF-2α. The current paradigm, established using mechanistic cell-based studies, supports a tumor promoting role for HIF-2α, and a tumor suppressor role for HIF-1α. However, few studies have comprehensively examined the clinical relevance of this paradigm. Furthermore, the hypoxia-associated factor (HAF), which regulates the HIFs, has not been comprehensively evaluated in ccRCC. EXPERIMENTAL DESIGN: To assess the involvement of HAF/HIFs in ccRCC, we analyzed their relationship to tumor grade/stage/outcome using tissue from 380 patients, and validated these associations using tissue from 72 additional patients and a further 57 patients treated with antiangiogenic therapy for associations with response. Further characterization was performed using single-cell mRNA sequencing (scRNA-seq), RNA-in situ hybridization (RNA-ISH), and IHC. RESULTS: HIF-1α was primarily expressed in tumor-associated macrophages (TAMs), whereas HIF-2α and HAF were expressed primarily in tumor cells. TAM-associated HIF-1α was significantly associated with high tumor grade and increased metastasis and was independently associated with decreased overall survival. Furthermore, elevated TAM HIF-1α was significantly associated with resistance to antiangiogenic therapy. In contrast, high HAF or HIF-2α were associated with low grade, decreased metastasis, and increased overall survival. scRNA-seq, RNA-ISH, and Western blotting confirmed the expression of HIF-1α in M2-polarized CD163-expressing TAMs. CONCLUSIONS: These findings highlight a potential role of TAM HIF-1α in ccRCC progression and support the reevaluation of HIF-1α as a therapeutic target and marker of disease progression.

Reliability and Validity of Proposed Risk Stratification Methods for Laboratory Developed Tests.

OBJECTIVES: To determine whether different laboratory developed test (LDT) risk stratification proposals would assign differing levels of risk to selected LDTs as a measure of the validity of those proposals, and whether there would be differing interrater agreement rates as a measure of the reliability of those proposals. METHODS: A total of 4 reviewers applied 6 proposals for risk stratification of 4 LDTs. Interrater agreement was calculated as a measure of the reliability of the proposals. Also, a consensus risk categorization and concordance rate for each LDT was developed as a measure of the validity of the proposals. RESULTS: Interrater agreement rates (reliability) ranged from 38% to 100%, and concordance rates (validity) ranged from 20% to 100%. CONCLUSIONS: A spectrum of reliability and validity was observed depending on the policy used and the LDT categorized. Before implementation or legislation of risk-stratification methods, large evaluations of reliability and validity should be conducted on any proposed method.

A Novel Presentation of Littoral Cell Angioma and Lymphatic Malformations in a Neonate.

This case report describes a novel presentation of littoral cell angioma (LCA) and lymphatic malformations involving the omentum and mesentery. To our knowledge, these 2 entities have not been reported in the same patient. A 1-month term infant male presented with chylous ascites. During his workup, imaging detected splenic nodules. Biopsies revealed that the nodules were LCA and the chylous ascites was secondary to microscopic mesenteric and omental lymphatic malformations. Evaluation for a secondary malignancy, an underlying immunologic defect, and genetic causes were unrevealing. The presence of LCA and lymphatic malformations in the same patient suggests a genetic link between these 2 rare vascular disorders and may help elucidate the etiopathogenesis of these 2 poorly understood anomalies.

Control of intestinal stem cell function and proliferation by mitochondrial pyruvate metabolism.

Most differentiated cells convert glucose to pyruvate in the cytosol through glycolysis, followed by pyruvate oxidation in the mitochondria. These processes are linked by the mitochondrial pyruvate carrier (MPC), which is required for efficient mitochondrial pyruvate uptake. In contrast, proliferative cells, including many cancer and stem cells, perform glycolysis robustly but limit fractional mitochondrial pyruvate oxidation. We sought to understand the role this transition from glycolysis to pyruvate oxidation plays in stem cell maintenance and differentiation. Loss of the MPC in Lgr5-EGFP-positive stem cells, or treatment of intestinal organoids with an MPC inhibitor, increases proliferation and expands the stem cell compartment. Similarly, genetic deletion of the MPC in Drosophila intestinal stem cells also increases proliferation, whereas MPC overexpression suppresses stem cell proliferation. These data demonstrate that limiting mitochondrial pyruvate metabolism is necessary and sufficient to maintain the proliferation of intestinal stem cells.