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Aims: Malignant tumours of the lacrimal apparatus are rare and frequently show a poor prognosis, with no clear therapeutic standards. Characterisation of the genetic landscape of these rare tumours is sparse, and therefore therapeutics generally follow those of their common salivary gland counterparts. To further clarify the pathophysiology and discover potential therapeutic targets, we investigated the genetic landscape of eight tumours of the lacrimal apparatus. Methods and results: DNA and RNA sequencing were performed to identify genetic mutations and gene fusions. Immunohistochemistry, fluorescence in‐situ hybridisation and reverse transcription–polymerase chain reaction followed by Sanger sequencing were performed to confirm the identified molecular alterations. Genetic alterations were detected in six tumours. Among five adenoid cystic carcinomas (ACC), four had confirmed alterations of MYB or MYBL1 genes, including a MYB::NFIB fusion, a MYBL1::NFIB fusion, a MYB amplification and a novel NFIB::THSD7B fusion. Mutations in genes encoding epigenetic modifiers, as well as NOTCH1, FGFR2 and ATM mutations, were also identified in ACCs. A carcinoma ex pleomorphic adenoma showed TP53 and CIC mutations and an amplification of ERBB2. A transitional cell carcinoma was associated with HPV16 infection. No genetic alteration was found for one adenocarcinoma, not otherwise specified. Conclusions: Our study highlights the variety of molecular alterations associated with lacrimal system tumours and emphasises the importance of molecular testing in these tumours, which can reveal potentially targetable mutations. Our results also reinforce the hypothesis of a common physiopathology of all ACCs, regardless of their primary location. [ABSTRACT FROM AUTHOR]

The diagnosis, histomolecular classes of breast cancers (luminal A, luminal B, HER2‐enriched, and basal‐like), and accurate prediction of prognosis are commonly determined using morphological and phenotypical analyses in clinical practice worldwide. Therapeutic strategies are mostly based on the disease stage and molecular subclasses of breast cancer. Targeted therapies, such as anti‐HER2s, poly‐ADP ribose polymerase inhibitors or, to a lesser extent, phosphatidylinositol 3 kinase inhibitors, have substantially improved breast cancer patient prognosis over the past decades. Human epidermal growth factor receptor 2 (HER2) overexpression is widely determined based on immunohistochemistry, while next‐generation sequencing (NGS) is currently employed to assess the presence of molecular alterations, including breast cancer gene 1 (BRCA1) and 2 or phosphatidylinositol‐4,5‐bisphosphate 3‐kinase catalytic subunit alpha (PIK3CA) mutations, which are targets of these new approved therapies. In addition, next‐generation sequencing (NGS) can aid the pathologist in challenging situations, such as a diagnostic workup for a metastatic carcinoma in lymph nodes of unknown origin, differential diagnosis of spindle cell tumourtumor in the breast between metaplastic carcinoma, malignant PT and sarcoma, o, as well as determining relatedness between primary breast cancers and recurrences. NGS offers a powerful tool that enables the pathologist to combine morphological analyses together with molecular alterations in challenging diagnostic situations. [ABSTRACT FROM AUTHOR]

Inverted duplication deletion 8p [invdupdel(8p)] is a complex and rare chromosomal rearrangement that combines a distal deletion and an inverted interstitial duplication of the short arm of chromosome 8. Carrier patients usually have developmental delay and intellectual disability (ID), associated with various cerebral and extra‐cerebral malformations. Invdupdel(8p) is the most common recurrent chromosomal rearrangement in ID patients with anomalies of the corpus callosum (AnCC). Only a minority of invdupdel(8p) cases reported in the literature to date had both brain cerebral imaging and chromosomal microarray (CMA) with precise breakpoints of the rearrangements, making genotype–phenotype correlation studies for AnCC difficult. In this study, we report the clinical, radiological, and molecular data from 36 new invdupdel(8p) cases including three fetuses and five individuals from the same family, with breakpoints characterized by CMA. Among those, 97% (n = 32/33) of patients presented with mild to severe developmental delay/ID and 34% had seizures with mean age of onset of 3.9 years (2 months–9 years). Moreover, out of the 24 patients with brain MRI and 3 fetuses with neuropathology analysis, 63% (n = 17/27) had AnCC. We review additional data from 99 previously published patients with invdupdel(8p) and compare data of 17 patients from the literature with both CMA analysis and brain imaging to refine genotype–phenotype correlations for AnCC. This led us to refine a region of 5.1 Mb common to duplications of patients with AnCC and discuss potential candidate genes within this region. [ABSTRACT FROM AUTHOR]

Background: High tumor mutational burden (TMB) was reported to predict the efficacy of immune checkpoint inhibitors (ICIs). Pembrolizumab, an anti-PD-1, received FDA-approval for the treatment of unresectable/metastatic tumors with high TMB as determined by the FoundationOne®CDx test. It remains to be determined how TMB can also be calculated using other tests. Results: FFPE/frozen tumor samples from various origins were sequenced in the frame of the Institut Curie (IC) Molecular Tumor Board using an in-house next-generation sequencing (NGS) panel. A TMB calculation method was developed at IC (IC algorithm) and compared to the FoundationOne® (FO) algorithm. Using IC algorithm, an optimal 10% variant allele frequency (VAF) cut-off was established for TMB evaluation on FFPE samples, compared to 5% on frozen samples. The median TMB score for MSS/POLE WT tumors was 8.8 mut/Mb versus 45 mut/Mb for MSI/POLE-mutated tumors. When focusing on MSS/POLE WT tumor samples, the highest median TMB scores were observed in lymphoma, lung, endometrial, and cervical cancers. After biological manual curation of these cases, 21% of them could be reclassified as MSI/POLE tumors and considered as "true TMB high." Higher TMB values were obtained using FO algorithm on FFPE samples compared to IC algorithm (40 mut/Mb [10–3927] versus 8.2 mut/Mb [2.5–897], p < 0.001). Conclusions: We herein propose a TMB calculation method and a bioinformatics tool that is customizable to different NGS panels and sample types. We were not able to retrieve TMB values from FO algorithm using our own algorithm and NGS panel. [ABSTRACT FROM AUTHOR]

Mainstreamed genetic testing (MGT) obviates the need for a cancer genetics consultation, since trained oncologists (O) and gynaecologists (G) provide counseling, prescribe testing and deliver results. We report results from our MGT program and emphasize its utility during the COVID-19 lockdown, when cancer genetics clinics had suspended their activity. An MGT pathway for breast and ovarian cancer (BC/OC) patients was established in Jan-2018 between the Assistance Publique - Hôpitaux de Paris.Sorbonne Université Cancer Genetics team and the Oncology/Gynecology departments at one teaching and two regional hospitals. Trained O + G evaluated patients with the Manchester Scoring System. A 12-point threshold was recommended for testing. Next-generation sequencing of BRCA1, BRCA2, PALB2, RAD51C and RAD51D was performed. Results were delivered to the patient by O/G. Pathogenic variants (PV) carriers were referred to the genetics clinic. Results are reported for the 2nd-Jan-2018 to 1st-June-2020 period. That includes the eight-week COVID-19 lockdown and three-week de-confinement phase 1. Results were available for 231/234 patients. Twenty-eight (12.1%) carried a PV. Of the 27 patients tested during the COVID-19 period, three carried a PV, two in BRCA1 and one in RAD51C. The clinical impact was immediate for the two BRCA1 BC cases undergoing neo-adjuvant chemotherapy, since double mastectomy and salpingo-oophorectomy will now be performed using two-step strategies. MGT guaranteed care continuity in BC/OC patients during the critical phases of the COVID-19 pandemic, with immediate implications for PV carriers. More broadly, we report for the first time the successful implementation of MGT in France. [ABSTRACT FROM AUTHOR]