Whole-Slide Mitosis Detection in H&E Breast Histology Using PHH3 as a Reference to Train Distilled Stain-Invariant Convolutional Networks

Manual counting of mitotic tumor cells in tissue sections constitutes one of the strongest prognostic markers for breast cancer. This procedure, however, is time-consuming and error-prone. We developed a method to automatically detect mitotic figures in breast cancer tissue sections based on convolutional neural networks (CNNs). Application of CNNs to hematoxylin and eosin (H&E) stained histological tissue sections is hampered by: (1) noisy and expensive reference standards established by pathologists, (2) lack of generalization due to staining variation across laboratories, and (3) high computational requirements needed to process gigapixel whole-slide images (WSIs). In this paper, we present a method to train and evaluate CNNs to specifically solve these issues in the context of mitosis detection in breast cancer WSIs. First, by combining image analysis of mitotic activity in phosphohistone-H3 (PHH3) restained slides and registration, we built a reference standard for mitosis detection in entire H&E WSIs requiring minimal manual annotation effort. Second, we designed a data augmentation strategy that creates diverse and realistic H&E stain variations by modifying the hematoxylin and eosin color channels directly. Using it during training combined with network ensembling resulted in a stain invariant mitosis detector. Third, we applied knowledge distillation to reduce the computational requirements of the mitosis detection ensemble with a negligible loss of performance. The system was trained in a single-center cohort and evaluated in an independent multicenter cohort from The Cancer Genome Atlas on the three tasks of the Tumor Proliferation Assessment Challenge (TUPAC). We obtained a performance within the top-3 best methods for most of the tasks of the challenge.Comment: Accepted to appear in IEEE Transactions on Medical Imagin

Two-Compartment or 4-Compartment Fasciotomy for Lower Leg Chronic Exertional Compartment Syndrome: A Systematic Review

Patients with lower leg chronic exertional compartment syndrome are impaired due to exercise-related pain. Fasciotomy is the surgical gold standard. However, it is unknown whether number of simultaneously opened compartments affects outcome. The purpose of this systematic review was to compare patient-reported outcomes of a 2-compartment fasciotomy with a 4-compartment fasciotomy. Controlled clinical trials (randomized/nonrandomized), cohort studies and case series reporting on outcome following either 2-compartment or 4-compartment fasciotomy for lower leg chronic exertional compartment syndrome were searched until May 31, 2021 in PubMed, EMBASE, and Cochrane. Results were qualitatively synthesized. Risk of bias and levels of evidence were determined. Seven studies reporting on altogether 194 athletes and military personnel (mean age 24 y) were included. Quality assessment revealed a high risk of bias in all studies. Both 2-compartment and 4-compartment fasciotomy were associated with a 50% to 100% "return to activity" rate (in studies reporting group results separately: 2-compartment 90%-100%; 4-compartment 50%-100%) and a 41% to 100% "return to previous activity" rate (in studies reporting group results separately: 2-compartment 82-100%; 4-compartment 50%-100%) without significant differences. Mean Marx activity score of 1 study found a small significant standardized mean difference (0.196 [0.524,0.916]) favoring 4-compartment fasciotomy. Rate of satisfaction (2-compartment 74%-89%; 4-compartment 75%-100%) and residual symptoms (2-compartment 0%-36%; 4-compartment 0%-50%) indicated no group differences. In conclusion, a 2-compartment fasciotomy or a 4-compartment fasciotomy for lower leg chronic exertional compartment syndrome appears to be equally successful. However, included studies were hampered by methodological shortcomings (low sample size, selection bias, heterogeneity and no uniform outcome measures)

Two-Compartment or 4-Compartment Fasciotomy for Lower Leg Chronic Exertional Compartment Syndrome:A Systematic Review

Patients with lower leg chronic exertional compartment syndrome are impaired due to exercise-related pain. Fasciotomy is the surgical gold standard. However, it is unknown whether number of simultaneously opened compartments affects outcome. The purpose of this systematic review was to compare patient-reported outcomes of a 2-compartment fasciotomy with a 4-compartment fasciotomy. Controlled clinical trials (randomized/nonrandomized), cohort studies and case series reporting on outcome following either 2-compartment or 4-compartment fasciotomy for lower leg chronic exertional compartment syndrome were searched until May 31, 2021 in PubMed, EMBASE, and Cochrane. Results were qualitatively synthesized. Risk of bias and levels of evidence were determined. Seven studies reporting on altogether 194 athletes and military personnel (mean age 24 y) were included. Quality assessment revealed a high risk of bias in all studies. Both 2-compartment and 4-compartment fasciotomy were associated with a 50% to 100% “return to activity” rate (in studies reporting group results separately: 2-compartment 90%-100%; 4-compartment 50%-100%) and a 41% to 100% “return to previous activity” rate (in studies reporting group results separately: 2-compartment 82-100%; 4-compartment 50%-100%) without significant differences. Mean Marx activity score of 1 study found a small significant standardized mean difference (0.196 [0.524,0.916]) favoring 4-compartment fasciotomy. Rate of satisfaction (2-compartment 74%-89%; 4-compartment 75%-100%) and residual symptoms (2-compartment 0%-36%; 4-compartment 0%-50%) indicated no group differences. In conclusion, a 2-compartment fasciotomy or a 4-compartment fasciotomy for lower leg chronic exertional compartment syndrome appears to be equally successful. However, included studies were hampered by methodological shortcomings (low sample size, selection bias, heterogeneity and no uniform outcome measures)

A DNA virus-encoded immune antagonist fully masks the potent antiviral activity of RNAi in Drosophila

International audienceCoevolution of viruses and their hosts may lead to viral strategies to avoid, evade, or suppress antiviral immunity. An example is antiviral RNA interference (RNAi) in insects: the host RNAi machinery processes viral double-stranded RNA into small interfering RNAs (siRNAs) to suppress viral replication, whereas insect viruses encode suppressors of RNAi, many of which inhibit viral small interfering RNA (vsiRNA) production. Yet, many studies have analyzed viral RNAi suppressors in heterologous systems, due to the lack of experimental systems to manipulate the viral genome of interest, raising questions about in vivo functions of RNAi suppressors. To address this caveat, we generated an RNAi suppressor-defective mutant of invertebrate iridescent virus 6 (IIV6), a large DNA virus in which we previously identified the 340R protein as a suppressor of RNAi. Loss of 340R did not affect vsiRNA production, indicating that 340R binds siRNA duplexes to prevent RNA-induced silencing complex assembly. Indeed, vsiRNAs were not efficiently loaded into Argonaute 2 during wild-type IIV6 infection. Moreover, IIV6 induced a limited set of mature microRNAs in a 340R-dependent manner, most notably miR-305-3p, which we attribute to stabilization of the miR-305-5p:3p duplex by 340R. The IIV6 340R deletion mutant did not have a replication defect in cells, but was strongly attenuated in adult Drosophila. This in vivo replication defect was completely rescued in RNAi mutant flies, indicating that 340R is a bona fide RNAi suppressor, the absence of which uncovers a potent antiviral immune response that suppresses virus accumulation ∼100-fold. Together, our work indicates that viral RNAi suppressors may completely mask antiviral immunity

Additional file 1: of Maturation toward neuronal tissue in a Ewing sarcoma of bone after chemotherapy

The used antibodies. (XLSX 10kb

Differential TGF-beta Signaling in Retinal Vascular Cells: A Role in Diabetic Retinopathy?

PURPOSE. An early hallmark of preclinical diabetic retinopathy is thickening of the capillary basal lamina (BL). TGF-beta, a multipotent cytokine acting through its receptors ALK5 and -1, has been postulated to be involved in this phenomenon. In light of this possible role, TGF-beta signaling and its downstream molecular effects were characterized in cultured vascular endothelial cells and pericytes of the retina. METHODS. Bovine retinal endothelial cells and pericytes were stimulated with TGF-beta 1 in the presence or absence of SD-208, a specific inhibitor of the TGF-beta type I receptor ALK5, or ALK5 small interfering (si) RNA. TGF-beta-signaling pathways were characterized by analysis of phosphorylated Smad2 or -1/5/8 proteins and TGF-beta target genes (PAI-1, fibronectin, CTGF, Smad7, and Id1) and protein (fibronectin). RESULTS. ALK5 was expressed in both cell types, whereas ALK1 was exclusively expressed in endothelial cells. In endothelial cells, TGF-beta induced Smad2 phosphorylation at high concentrations, which was efficiently blocked by ALK5 inhibition. In contrast, in pericytes, Smad2 phosphorylation was rapidly induced at low concentrations of TGF-beta. The ALK1-Smad1/5/8 pathway was activated by TGF-beta in endothelial cells only. TGF-beta caused ALK5-mediated upregulation of PAI-1, Smad7, and fibronectin and in pericytes at lower TGF-beta concentrations than in endothelial cells. CTGF mRNA expression was induced only in pericytes. Fibronectin protein was confirmed to be regulated by TGF-beta in both cell types. CONCLUSIONS. TGF-beta signaling in retinal endothelial cells and pericytes show that these cells, and in particular the pericytes, have the essential characteristics to allow for a role of TGF-beta in BL thickening in preclinical diabetic retinopathy. (Invest Ophthalmol Vis Sci. 2010; 51:1857-1865) DOI: 10.1167/iovs.09418

Solitary fibrous tumor – clinicopathologic, immunohistochemical and molecular analysis of 28 cases

BACKGROUND: Solitary fibrous tumor is a mesenchymal tumor of fibroblastic type, which can affect any region of the body. Recently, a recurrent gene fusion NAB2-STAT6 has been identified as molecular hallmark. The NAB2-STAT6 fusion leads to EGR1 activation and transcriptional deregulation of EGR1-dependent target genes and is a driving event in initiation of SFT. In this study, we report the clinicopathologic and RT-PCR findings and evaluated expression of STAT6 and EGR1 protein in a cohort of 28 SFTs. METHODS: 28 patients with a median age of 54 years were included with SFTs originating at different sites, most occurring in the lung and pleura (9, 32%), 5 in soft tissues of the lower extremities (18%) and 5 in the head and neck (18%). For detection of the NAB2-STAT6 fusion gene, RT-PCR was performed using RNA extracted from formalin-fixed and paraffin-embedded tissues. Immunohistochemistry was performed on all cases with antibodies against STAT6 and EGR1. RESULTS: All patients were treated by surgery, 3 with adjuvant chemo- or radiotherapy. Follow-up data of 18 patients could be obtained of which 2 patients died of metastatic disease 13 months and 52 years after first diagnosis. Sixteen patients have no evidence of disease with a median follow up of 29.5 months (range 7 – 120 months). NAB2-STAT6 fusion transcripts were found in 19/28 cases (68%). The most common fusion was between NAB2 exon 4 and STAT6 exon 3 (11/19, 58%), mainly occurring in pleuropulmonary lesions. All cases showed strong nuclear expression of STAT6 (28/28, 100%) while EGR1 showed low-level variable nuclear expression in all samples, comparable with the EGR1 expression results of the control group. CONCLUSIONS: The identification of the NAB2-STAT6 fusion in SFTs can provide important diagnostic information, especially in cases with aberrant morphology or when biopsy material is limited. STAT6 immunohistochemistry is another useful tool in diagnosing SFT. EGR1 immunohistochemistry indicates low-level protein expression in accordance with EGR1 activation due to distorted NAB2 activity. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_22

Grading of Meningeal Solitary Fibrous Tumors/Hemangiopericytomas: Prognostic Value of the Marseille Grading System in a Cohort of 132 Patients in correlation with molecular data

19th International Congress of Neuropathology, Tokyo, JAPAN, SEP 23-27, 2018International audienc