PAX3-NCOA1 alveolar rhabdomyosarcoma of the tongue: A rare entity with challenging diagnosis and management.

AbstractAlveolar rhabdomyosarcoma (ARMS) is associated with PAX3/PAX7‐FOXO1 fusion, which confers specific clinic and biologic characteristics with inferior outcomes. A minority of tumors still histologically classified as "true" ARMS lack the canonical PAX‐FOXO1 fusion but have new molecular alterations. We present the first case of PAX3‐NCOA1 ARMS with clinical data and follow‐up in a two‐year‐old girl with ARMS of the tongue and nodal extension, treated with chemotherapy, hemi glossectomy, lymph node dissection, and brachytherapy to conserve oral function and limit long‐term sequelae. Given the rarity of such variant fusion in ARMS, international collaboration is required to evaluate its prognostic value

Nucleocytoplasmic Shuttling of Pak5 Regulates Its Antiapoptotic Properties

p21-activated kinase 5 (Pak5) is an effector for the small GTPase Cdc42, known to activate cell survival signaling pathways. Previously, we have shown that Pak5 localizes primarily to mitochondria. To study the relationship between Pak5 localization and its effects on apoptosis, we identified three N-terminal regions that regulate the localization of this kinase: a mitochondrial targeting sequence, a nuclear export sequence, and a nuclear localization sequence. When the first two sequences are deleted, Pak5 is retained in the nucleus and no longer protects cells from apoptosis. Moreover, blockade of nuclear export with leptomycin B causes endogenous Pak5 to accumulate in the nucleus. Additionally, the removal of the N-terminal nuclear localization sequence abolishes Pak5 translocation to the nucleus. Finally, we show that reduction of endogenous Pak5 expression in neuroblastoma and neural stem cells increases their sensitivity to apoptosis and that this effect is reversed upon reexpression of wild-type Pak5 but not of a mutant form of Pak5 that cannot localize to mitochondria. These results show that Pak5 shuttles from mitochondria to the nucleus and that the mitochondrial localization of Pak5 is vital to its effects on cell survival

Targeting CDC25C, PLK1 and CHEK1 to overcome Docetaxel resistance induced by loss of LZTS1 in prostate cancer

International audienceDocetaxel is used as a standard treatment in patients with metastatic castration-resistant prostate cancer. However, a large subset of patients develops resistance. Understanding resistance mechanisms, which are largely unknown, will allow identification of predictive biomarkers and therapeutic targets. We established resistant IGR-CaP1 prostate cancer cell lines for different doses of Docetaxel. We investigated gene expression profiles by microarray analyses in these cell lines and generated a signature of 99 highly differentially expressed genes potentially implicated in chemoresistance. We focused on the role of the cell cycle regulator LZTS1, which was under-expressed in the Docetaxel-resistant cell lines, its inhibition resulting from the promoter methylation. Knockdown of LZTS1 in parental cells with siRNA showed that LZTS1 plays a role in the acquisition of the resistant phenotype. Furthermore, we observed that targeting CDC25C, a partner of LZTS1, with the NSC663284 inhibitor specifically killed the Docetaxel-resistant cells. To further investigate the role of CDC25C, we used inhibitors of the mitotic kinases that regulate CDC25C. Inhibition of CHEK1 and PLK1 induced growth arrest and cell death in the resistant cells. Our findings identify an important role of LZTS1 through its regulation of CDC25C in Docetaxel resistance in prostate cancer and suggest that CDC25C, or the mitotic kinases CHEK1 and PLK1, could be efficient therapeutic targets to overcome Docetaxel resistance

A novel fusion variant LSM14A :: NR4A3 in extraskeletal myxoid chondrosarcoma

International audienceAbstract Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue neoplasm of uncertain lineage characterized by the pathognomonic rearrangement of the NR4A3 gene, which in most cases is fused with EWSR1. Other NR4A3 fusion partners have been described, namely TAF15 , FUS , TCF12, and TGF . Some studies suggest that EMCs with non‐ EWSR1 variant fusion are associated with high‐grade morphology and worst clinical behavior compared to EWSR1::NR4A3 tumors, supporting the potential significance of particular fusion variant in EMC. We report a case of a 34‐year‐old male who presented with calf EMC and subsequently developed a slowly progressive metastatic disease 3 years after diagnosis. Whole‐transcriptome analysis with total RNA sequencing enabled identification of a novel fusion transcript LSM14A::NR4A3 , expanding the molecular spectrum of EMC

Incidents in Molecular Pathology: Frequency and Causes During Routine Testing.

CONTEXT.— Errors in laboratory medicine could compromise patient safety. Good laboratory practice includes identifying and managing nonconformities in the total test process. Varying error percentages have been described in other fields but are lacking for molecular oncology. OBJECTIVES.— To gain insight into incident causes and frequency in the total test process from 8 European institutes routinely performing biomarker tests in non-small cell lung cancer and colorectal cancer. DESIGN.— All incidents documented in 2018 were collected from all hospital services for pre-preanalytical entries before the biomarker test, as well as specific incidents for biomarker tests. RESULTS.— There were 5185 incidents collected, of which 4363 (84.1%) occurred in the pre-preanalytical phase (all hospital services), 2796 of 4363 (64.1%) related to missing or incorrect request form information. From the other 822 specific incidents, 166 (20.2%) were recorded in the preanalytical phase, 275 (33.5%) in the analytical phase, and 194 (23.6%) in the postanalytical phase, mainly due to incorrect report content. Only 47 of 822 (5.7%) incidents were recorded in the post-postanalytical phase, and 123 (15.0%) in the complete total test process. For 17 of 822 (2.1%) incidents the time point was unknown. Pre-preanalytical incidents were resolved sooner than incidents on the complete process (mean 6 versus 60 days). For 1215 of 5168 (23.5%) incidents with known causes a specific action was undertaken besides documenting them, not limited to accredited institutes. CONCLUSIONS.— There was a large variety in the number and extent of documented incidents. Correct and complete information on the request forms and final reports are highly error prone and require additional focus

Next-Generation Sequencing on Circulating Tumor DNA in Advanced Solid Cancer: Swiss Army Knife for the Molecular Tumor Board? A Review of the Literature Focused on FDA Approved Test

FDA-approved next-generation sequencing assays based on cell-free DNA offers new opportunities in a molecular-tumor-board context thanks to the noninvasiveness of liquid biopsy, the diversity of analyzed parameters and the short turnaround time. It gives the opportunity to study the heterogeneity of the tumor, to elucidate complex resistance mechanisms and to adapt treatment strategies. However, lowering the limit of detection and increasing the panels’ size raise new questions in terms of detection of incidental germline alterations, occult malignancies and clonal hematopoiesis of indeterminate potential mutations. In this review, after a technological discussion and description of the common problematics encountered, we establish recommendations in properly using these FDA-approved tests in a molecular-tumor-board context