WHO CLASSIFICATION 2022, BETHESDA SYSTEM 2023, MOLECULAR BIOLOGY AND MOLECULAR TESTING: Thyroid pathology has experienced significant advances with the publication of the 5th edition of the World Health Organization classification of endocrine tumors in 2022 and the third edition of the Bethesda system for thyroid cytopathology in 2023. At the same time, the availability of next-generation sequencing data coupled with numerous translational research projects have considerably increased our knowledge of the genomics and mechanics of thyroid cancers, enabling us to refine prognosis and propose new targeted therapies. In this review, we will take up the main new features of the WHO 2022 and Bethesda 2023 classifications, as well as molecular biology findings, with an emphasis on the practical implications for clinicians.

Non-small cell lung cancers (NSCLC) are the most common lung cancers, withpeak incidence at 65years of age. These cancers rarely occur before the age of 40.

This review focuses on uterine mesenchymal tumors that are defined on a molecular level by a single and unique genetic alteration, that is somehow necessary and sufficient to allow tumor growth and progression. Although diverse from a clinical, morphological and immunohistochemical point of view, the different entities we are going to talk about share both a simple genomic profile with a low number of chromosomal alterations observed by CGH Array (few deletions, gains or amplifications...) and a low mutational burden observed by sequencing technics. Some of these entities are already well known and described in the literature when found outside of the uterus and gynecological tract. It remains intriguing that uterine mesenchymal pathology has been lagging behind when compared to its extrauterine counterpart. How can we explain that when it comes to inflammatory myofibroblastic tumors, abundant numbers of articles have been published since the 70's, but it was only in the early 2000s that the first relevant descriptions of this tumor in the uterus emerged? Certainly, the increased accuracy, availability, and use of molecular biology technics and in particular RNA sequencing in the area of uterine pathology can partly explain the reduction of the gap between soft tissue and uterine pathology we currently observe. Other reasons explaining this gap may be the high prevalence of smooth muscle tumors in the uterus and the abounding diversity of their morphological aspects, which may have partly eclipsed the array of differential diagnoses. Last but not least, one can hypothesize that the relative "simplicity" of hysterectomy procedures, referring to their safety and accessibility, has cured most of the lesions and partly clouded our knowledge regarding the biological potential and natural history of these newly described entities. As a consequence of this situation, our reader will often encounter the wording "uncertain malignant potential", as for some of these rare entities, evidence to establish reliable prognostic variables is still insufficient. We hope this review to be a useful tool to guide pathologists through the diversity and complexity of uterine mesenchymal tumors. As a scientific and medical community, sharing this knowledge will help us to collectively raise our vigilance and awareness by expanding the array of our differential diagnoses. We hope this will lead to more cases being accurately diagnosed, and ultimately, to a deeper knowledge regarding the biological potential and clinical evolution of these tumors. From a therapeutical point of view, the consequences of an accurate diagnosis for the patient are already appreciable through the use of targeted therapy. Examples include: ALK inhibitors in inflammatory myofibroblastic tumor, tyrosine-kinase inhibitors in COL1A::PDGFB rearranged sarcomas or mTOR inhibitors in PEComa.

The prognostic of certain cancers improved significantly in recent years thanks not only to the launch of innovative treatments but also to progress made in the diagnostic field. Thus, next-generation sequencing (NGS) became paramount to help characterizing tumors and selecting the most pertinent treatments. The survey conducted by a multi stakeholder committee, at the end of 2022, with 103 actors of the management of cancer patients (public and private centers, labs, prescribers, biologists, pathologists, direction) confirmed the heterogeneity of use of NGS tests across France due to, mainly, the lack of systematic reimbursement of related costs. Référentiel des actes innovants hors nomenclature de biologie (RIHN) covers, in a delayed and partial way, only half of costs engaged by centers. Only those with a critical mass of patients or with a sufficient funding capacity can guarantee an access to large panels. Postponing the initiation of a required treatment represents a risk of loss of opportunity for patients who cannot benefit of this technology. NGS large panels tests, an efficiency lever for cancer treatment, must be part of the care toolbox. Those with a demonstration of value created should nowadays be fully reimbursed by collectivity after HAS' evaluation, for a fair access throughout the territory. Precision diagnostic can open the way to a more personalized and efficient medicine.

Molecular profiling has become essential in the management of patients with biliary tract cancer (BTC). The aim of this study was to evaluate the practices of French genetics platforms in the management of BTCs.

In 2019, the 5th edition of the WHO classification of digestive tumours has retained the terminology "goblet cell adenocarcinoma" (GCA) to designate a tumour whose amphicrine nature owed it more than ten denominations since its initial description among which the most tenacious "goblet cell carcinoid" is no longer recommended today. This rare tumour represents 15-19% of appendicular tumours. Its incidence is rising. The positive diagnosis is based on morphological examination and mandatory identification of a low-grade component of glands comprising goblet cells stained by PAS and Alcian blue. The appendix must be entirely examined. Global tumour grade (low, intermediate, high) is based on the proportions of low-grade and high-grade components. This tumour's immunohistochemical profile is particular because of expression of CK20 and often CK7 as well as neuroendocrine markers. It is often an incidental finding on a surgical specimen, among individuals aged 50 or more years, presenting with a locally advanced stage with vascular and perineural invasion. Lymph node metastases are present in a third of cases. Non-specific mutations of ARID1A and genes of the Wnt pathway may be identified. GCA is not associated with microsatellite instability or Lynch syndrome. Its prognosis is intermediate. Surgery is the reference therapy based on the stage. The main differential diagnoses are colorectal adenocarcinoma NOS, mucinous adenocarcinoma and signet ring cell adenocarcinoma. Patients are referred to the RENAPE expert network.

The grading of glial tumors is based on morphological and sometimes on molecular features. Many markers have been assessed in order to grade the glial tumours without a real consensus. Some authors reported that SRSF1, a spiling factor, presents an expression correlated to the tumours grades.

Castration-resistant metastatic prostate cancer remains lethal and a therapeutic challenge. Current strategies are geared towards the personalization of treatments based on the identification of relevant molecular targets, including genomic alterations involved in tumoral processes. Among these novel targeted therapies, poly-ADP-ribose polymerase inhibitors (PARPi), by blocking the action of enzymes involved in deoxyribonucleic acid (DNA) repair, induce the destruction of cells carrying defects in homologous recombination repair, often associated with alterations in genes involved in this mechanism. Thus, determining the presence of a molecular anomaly, particularly alterations in the BRCA1/2 genes, is a prerequisite for initiating PARPi monotherapy. In patients with metastatic castration-resistant prostate cancer , around 20-30 % carry this type of mutation. In this population, single-agent studies have demonstrated PARPi ability to prolong overall survival, and to improve symptom control, including pain. Other studies are underway to assess their effectiveness in combination with other therapies, and it already appears that association with new-generation hormone therapy can further prolong radiological progression-free survival, regardless of the mutation status of the genes involved in DNA repair, indicating a synergistic action between PARPi and new-generation hormone therapy.

RUNX1 is essential during human hematopoiesis. Numerous RUNX1 deregulations have been described, including translocations and germline or somatic mutations. Recurrent de novo RUNX1 mutations in acute myeloid leukemias (AML) prompted the creation of a provisional entity of AML with mutated RUNX1 in the 2016 WHO. In addition, recent genomic studies underlined rare AML patients with plasmacytoid dendritic cell (pDC) expansion and high RUNX1 mutations frequency. To better characterized AML with RUNX1 mutations, we retrospectively investigated a cohort of 32 patients diagnosed at Strasbourg University Hospital. Detailed clinical and biological features were aggregated. The presence of a pDC contingent was assessed by cytology and flow cytometry. In our cohort, no common features were identified either in term of cytology, stage of leukemia arrest or mutational features. Based on our observations, mutated RUNX1 AMLs do not appear to be a distinct AML entity. The new 2022 WHO classification includes AML with mutated RUNX1 within AML myelodysplasia-related category. We also identified within our cohort a patient whose AML fulfilled AML-pDC criteria, a rare and newly included entity in the last WHO classification.

The rising global incidence of cancer makes it the second leading cause of death worldwide. Over the past decades, significant progress has been made in both basic knowledge and the discovery of new therapeutic approaches. However, the complexity of mechanisms related to tumor development requires the use of sophisticated and adapted research tools. Among these, the fruitfly Drosophila melanogaster represents a powerful genetic model with numerous practical and conceptual advantages. Indeed, the conservation of genes implicated in cancer between this insect and mammals places Drosophila as a crucial genetic tool for understanding the fundamental mechanisms governing tumorigenesis and identifying new therapeutic targets. This review aims to describe this original model and demonstrate its relevance for studying cancer biology.

Treatment of pediatric high-risk acute myeloid leukemia (AML), defined either on molecular or cytogenetic features, relies on bone marrow transplant after cytologic remission. However, relapse remains the first post-transplant cause of mortality. In this 13th session of practice harmonization of the francophone society of bone marrow transplantation and cellular therapy (SFGM-TC), our group worked on recommendations regarding the management of post-transplant relapse in AML pediatric patients based on international literature, national survey and expert opinion. Overall, immunomodulation strategy relying on both measurable residual disease (MRD) and chimerism evaluation should be used for high-risk AML. In very high-risk (VHR) AML with a 5-year overall survival ≤30 %, a post-transplant maintenance should be proposed using either hypomethylating agents, combined with DLI whenever possible, or FLT3 tyrosine kinase inhibitors if this target is present on leukemia cells. In the pre-emptive or early relapse settings (< 6 months post-transplant), treatments combining DLI, Azacytidine and Venetoclax should be considered. Access to phase I/II trails for targeted therapies (menin, IDH or JAK inhibitors) should be discussed in each patient according to the underlying molecular abnormalities of the disease.

Despite screening programmes, numerous clinical studies and new breast imaging techniques, breast cancer incidence for women continues to rise. The arrival of predictive and personalized medicine could clearly redefine our screening recommendations. One promising approach to improving screening would be to use tools to predict the risk of developing breast cancer, including polygenic risk scores (PRS). This approach will enable us to offer women risk-based screening by adapting the frequency, type and age of screening. This article reviews some definitions of the PRS and breast cancer screening. We also explain the risk assessment models that have been developed and the various studies underway on personalized screening.

Cutaneous adnexal tumours are a heterogeneous group of epithelial lesions that includes tumours with follicular, sudoral and/or sebaceous differentiation, or even several combined lines of differentiation. Over the last few years, molecular analysis of these lesions has allowed to identify specific molecular events responsible for tumour development in an increasing number of tumour types. Like other rare neoplasms, such as soft tissue tumours, adnexal tumours display fusion genes resulting from chromosomal translocations that may be specific for the diagnosis if molecular data are properly integrated in the clinical and morphological setting. Molecular testing of adnexal tumours is valuable as it allows to strengthen the robustness of the diagnosis for a group of tumours displaying a wide morphological spectrum. It has allowed to refine the diagnostic criteria and to develop increasingly specific diagnostic immunostainings. Finally, molecular testing has been responsible for the identification of new entities or morphological subtypes of previously known entities. The aim of this review is to provide an update on cutaneous adnexal tumours associated with fusion genes and to evaluate the impact of molecular data on the diagnosis of these lesions.

We report the case of a 14 year-old teenager who has SC hemoglobinosis and presented with a tumor syndrome with a retro-peritoneal mass, a supraclavicular lymph node and a mid-renal lesion. The microscopic examination revealed an undifferentiated tumor proliferation infiltrating the lymph node parenchyma. This tumor proliferation was INI1/SMARCB1-deficient, and expressed cytokeratins. Given the fact that the histopathological data showed an undifferentiated INI1-deficient carcinoma and that the patient has a kidney lesion and a sickle cell trait, the final diagnosis was lymph node metastasis of SMARCB1-deficient renal medullary carcinoma (OMS 2022).

CONTRIBUTIONS OF MOLECULAR BIOLOGY TO THE MANAGEMENT OF COLORECTAL CANCER. Colorectal cancer (CRC) is a major public health problem affecting almost 43.000 people a year and causing 17.000 deaths. Advances in molecular biology have made it possible to identify some of the mechanisms involved in colorectal carcinogenesis and tumor proliferation. Some molecular alterations are now routinely investigated to adapt follow-up and therapeutic decisions in both localized and metastatic CRC.

Targeted therapies are the standard first-line treatment for metastatic lung adenocarcinoma with certain molecular abnormalities. These abnormalities are particularly common in Southeast Asia and French Polynesia. A 51-year-old Tahitian female non-smoker was diagnosed in 2018 with stage IV lung adenocarcinoma harboring a p.L858R EGFR mutation. She received gefitinib as first-line treatment. Due to locoregional progression and the presence of a resistance mutation (p.T790M of EFGR), she received osimertinib as second-line treatment, after which chemotherapy was proposed as 3rd-line treatment. An additional biopsy detected not only the previously known EGFR mutation, but also a BRAF p.V600E mutation. Following disease progression during chemotherapy, the patient received targeted therapies combining dabrafenib, trametinib and osimertinib. Due to a dissociated response after four months of treatment, a 5th line of paclitaxel bevacizumab was initiated. Subsequent to additional progression and given the ALK rearrangement shown on the re-biopsy, 6th-line treatment with alectinib was proposed. As the response was once again dissociated, a final line was proposed before stopping active treatments due to their toxicity and overall deterioration in the patient's state of health. This exceptional case is characterized by resistance to anti-EGFR through the successive and cumulative acquisition of two new oncogene addictions. The authors underline the importance of re-biopsy at each progression, leading (if at all feasible) to yet around round of targeted therapy.

Cystic lung diseases are rare, with numerous differential diagnoses. Iconographic discovery consequently necessitates medical examinations in view of proposing an etiological orientation.