FISH and immunohistochemical status of the hepatocyte growth factor receptor (c-Met) in 184 invasive breast tumors

Grants PI05/0961 and PI06/1513 from Ministerio de Sanidad y Consumo ISCIII and RTICC 06/0020/1

Bridging the Gap: Immunotherapy in Progressive Multifocal Leukoencephalopathy: A New Hope?

Progressive multifocal leukoencephalopathy (PML) is a severe infection of the central nervous system occurring in immunocompromised individuals in which large demyelinating lesions are induced by polyomavirus JC (JCV). In the absence of effective antiviral treatment, control of the infection relies on restoring anti-JCV immunity. Thus, particularly in longstanding immunocompromising conditions such as organ transplantation, lymphoproliferative disorders, or idiopathic lymphopenia, new strategies to boost anti-JCV immune responses are needed. Here, we report the case of a patient developing PML in the context of kidney transplantation who received rh-IL-7 to foster immune responses against JCV. We give an overview of the immunological mechanisms underlying the development of PML and immune restoration within the central nervous system following JCV infection. Immunotherapeutic strategies developed based on current understanding of the disease hold promise in managing patients with PML

Pathologist computer-aided diagnostic scoring of tumor cell fraction: A Swiss national study.

Tumor cell fraction (TCF) estimation is a common clinical task with well-established large inter-observer variability. It thus provides an ideal testbed to evaluate potential impacts of employing a computer-aided diagnostic (TCFCAD) tool to support pathologists' evaluation. During a National Slide Seminar event, pathologists (n=69) were asked to visually estimate TCF in 10 regions of interest (ROI) from hematoxylin and eosin (H&E) colorectal cancer images intentionally curated for diverse tissue compositions, cellularity, and stain intensities. Next, they re-evaluated the same ROIs while being provided a TCFCAD created overlay highlighting predicted tumor versus non-tumor cells, together with the corresponding TCF percentage. Participants also reported confidence levels in their assessments using a 5-tiers scale, indicating no confidence to high confidence, respectively. The TCF ground truth (GT) was defined by manual cell-counting by experts. When assisted, inter-observer variability significantly decreased, showing estimates converging to the GT. This improvement remained even when TCFCAD predictions deviated slightly from the GT. The standard-deviation of estimated TCF to the GT across ROIs was 9.9% vs 5.8% with TCFCAD, p < 0.0001. The intraclass correlation coefficient increased from 0.8 to 0.93 (CI95% [0.65, 0.93] vs [0.86, 0.98]) and pathologists stated feeling more confident when aided (3.67 ± 0.81 vs. 4.17 ± 0.82 with CAD). TCFCAD estimation support demonstrated improved scoring accuracy, inter-pathologist agreement and scoring confidence. Interestingly, pathologists also expressed more willingness to use such a CAD tool at the end of the survey, highlighting the importance of training/education to increase adoption of CAD systems

The density of CD8+ T-cell infiltration and expression of BCL2 predicts outcome of primary diffuse large B-cell lymphoma of bone

HP

Validation of the 4B5 rabbit monoclonal antibody in determining Her2/neu status in breast cancer

HER2 overexpression in breast cancer is associated with worse clinical outcome. To select patients for anti-Her2-based therapy immunohistochemistry is commonly performed as a first step to assess Her2 status. However, interobserver and interlaboratory variability can significantly compromise adequate assessment of Her2 status. In addition, immunohistochemistry does not always result in an unambiguous test result requiring additional testing for Her2 gene amplification. This study aimed to improve the reliability of Her2 immunohistochemistry by using rabbit monoclonal antibody 4B5 as an alternative to mouse monoclonal antibody CB11 routinely used in our laboratory. Therefore, 283 breast adenocarcinomas were included in a tissue microarray. Immunohistochemistry using the 4B5 and CB11 antibodies, and fluorescence and chromogenic in situ hybridization (FISH or CISH) were performed. Immunohistochemistry was scored by two independent investigators. We found that 4B5 staining was more distinct than CB11 staining. For CB11 staining, there were 12% (BV) and 5% (JW) 2 + scores compared with 4% (BV) and 2% (JW) for 4B5. There was a strong trend towards higher interobserver agreement for 4B5 compared with CB11 (4B5: kappa 0.87, 95% CI 0.79-0.96; CB11: kappa 0.77, 95% CI 0.66-0.88). There were no significant differences in sensitivity, specificity and predictive values between CB11 and 4B5. Our results indicate that the 4B5 antibody provides more robust assessment of immunohistochemical Her2/neu status and will reduce the number of gene amplification tests compared with CB11. However, for tumours with a 2 + score additional gene amplification measurement using FISH or CISH remains necessary. Modern Pathology (2009) 22, 879-886; doi: 10.1038/modpathol.2009.37; published online 20 March 2009

Developmental and oncogenic programs in H3K27M gliomas dissected by single-cell RNA-seq.

Gliomas with histone H3 lysine27-to-methionine mutations (H3K27M-glioma) arise primarily in the midline of the central nervous system of young children, suggesting a cooperation between genetics and cellular context in tumorigenesis. Although the genetics of H3K27M-glioma are well characterized, their cellular architecture remains uncharted. We performed single-cell RNA sequencing in 3321 cells from six primary H3K27M-glioma and matched models. We found that H3K27M-glioma primarily contain cells that resemble oligodendrocyte precursor cells (OPC-like), whereas more differentiated malignant cells are a minority. OPC-like cells exhibit greater proliferation and tumor-propagating potential than their more differentiated counterparts and are at least in part sustained by <i>PDGFRA</i> signaling. Our study characterizes oncogenic and developmental programs in H3K27M-glioma at single-cell resolution and across genetic subclones, suggesting potential therapeutic targets in this disease

Neurogenic Potential of Engineered Mesenchymal Stem Cells Overexpressing VEGF

Numerous signaling molecules are altered following nerve injury, serving as a blueprint for drug delivery approaches that promote nerve repair. However, challenges with achieving the appropriate temporal duration of recombinant protein delivery have limited the therapeutic success of this approach. Genetic engineering of mesenchymal stem cells (MSCs) to enhance the secretion of proangiogenic molecules such as vascular endothelial growth factor (VEGF) may provide an alternative. We hypothesized that the administration of VEGF-expressing human MSCs would stimulate neurite outgrowth and proliferation of cell-types involved in neural repair. When cultured with dorsal root ganglion (DRG) explants in vitro, control and VEGF-expressing MSCs (VEGF-MSCs) increased neurite extension and proliferation of Schwann cells (SCs) and endothelial cells, while VEGF-MSCs stimulated significantly greater proliferation of endothelial cells. When embedded within a 3D fibrin matrix, VEGF-MSCs maintained overexpression and expressed detectable levels over 21 days. After transplantation into a murine sciatic nerve injury model, VEGF-MSCs maintained high VEGF levels for 2 weeks. This study provides new insight into the role of VEGF on peripheral nerve injury and the viability of transplanted genetically engineered MSCs. The study aims to provide a framework for future studies with the ultimate goal of developing an improved therapy for nerve repair