Arnaud Uguen

Some pancreatic ductal-type (PDADK) and lung adenocarcinomas (LADK) lacking other molecular drivers are reported to harbor NRG1 fusions as potential novel therapeutic targets. We investigated the feasibility of a fluorescent in situ hybridization (FISH)-based diagnosis of NRG1 fusions in a case series of PDADK and LADK lacking other identified oncogenic drivers. First, among a case series of PDADK, KRAS analyses (PCR followed in PCR-negative cases by RNA sequencing—RNAseq) found 27/162 (16.7%) KRAS wild-type cases, among which 1/162 (0.6%) NRG1 fusion was diagnosed using FISH. Secondly, among a case series of LDAK, 191/446 (42.8%) cases had no molecular alterations in EGFR, KRAS, BRAF, HER2, MET, ALK, ROS1 and RET according to NGS and FISH analyses and, among them, 4/446 (0.9%) cases had NRG1 fusions using FISH. Finally, four additional cases out of the two previously mentioned cases series (1 PDADK and 3 LADK) with NRG1 fusions diagnosed by first-line RNAseq were also concluded as NRG1 FISH-positive. The NRG1 FISH tests for the nine NRG1 FISH-positive cases resulted in 50% to 80% of positive tumor nuclei, all with single 3′-NRG1 FISH signals. In our series, of the 22 cases analyzed with both NRG1 FISH (positivity criterion of at least 15% of tumor nuclei with a split between the 5′- and the 3′- parts of the probes and/or isolated single 3′-NRG1 signal) and RNAseq, 17 cases were FISH– RNAseq– and 5 cases were FISH+ RNAseq+ (no FISH+ RNAseq– or FISH– RNAseq+ cases in our study) resulting in 100% sensibility and specificity for the NRG1 FISH test. In the case of no access to RNAseq, NRG1 FISH consists of a valuable tool searching for NRG1 fusions in patients with advanced cancers.

We studied the pathologists’ agreements in quantifying PD-L1 expression through the tumor proportion score (TPS) and the combined positive score (CPS) using single PD-L1 immunohistochemistry (S-IHC) and double immunohistochemistry (D-IHC) combining PD-L1 staining and tumor cell markers. S-IHC and D-IHC were applied to 15 cancer samples to generate 60 digital IHC slides (30 whole slides images and 30 regions of interest of 1 mm²) for PD-L1 expression quantification using both TPS and CPS, twice by four pathologists. Agreements were estimated calculating intraclass correlation coefficients (ICC). Both S-IHC and D-IHC slides analyses resulted in excellent (for TPS, ICC > 0.9) to good (for CPS, ICC > 0.75) inter- and intra-pathologist agreements with slightly higher ICC with D-IHC than with S-IHC. S-IHC resulted in higher TPS and CPS than D-IHC (+5.6 and +6.1 mean differences, respectively). High reproducibility in the quantification of PD-L1 expression is attainable using S-IHC and D-IHC.

Aims: We aimed to evaluate the performances of the Idylla GeneFusion Assay (IGFA) designed to detect, in a single, rapid and fully automated assay,ALK,ROS1,RET,NTRK1,NTRK2andNTRK3gene fusions andMETexon 14 skipping in cancer samples.Methods: Based on a set of tumours enriched in cases with gene fusions, we applied the IGFA to tumour areas of various sizes and tumour cell contents. IGFA results were compared with those obtained with other methods (immunohistochemistry, fluorescent in situ hybridisation, DNA and RNA next-generation sequencing).Results: We selected 68 tumours: 49 cases with known gene fusions (8ALK, 8ROS1, 5RET, 7NTRK1, 3NTRK2and 6NTRK3ones) orMETexon 14 skipping mutations (12 cases) and 19 cases with no fusion and noMETmutation. We performed 128 IGFA tests on distinct tissue areas. The global sensitivity and specificity of the IGFA were, respectively, 62.82% and 99.2% with variations between molecular targets and tissue areas. Of note, 72.5% sensitivity and 98.79% specificity were obtained in 37 tissue areas fulfilling the manufacturer’s recommendations (ie, at least 10% of tumour cells in at least 20 mm² of tissue area). The rate of non-conclusive results was higher in small samples with low percentages of tumour cells.Conclusions: The IGFA could contribute to the rapid detection of targetable gene fusions and mutations, especially in context of rapidly growing cancers requiring urgent therapeutic choices.

(1) Background: Placental histological lesions reported in relation with SARS-CoV-2 infection are various, with potential consequences such as fetal growth retardation, prematurity or stillbirth/neonatal death. We report here on a placental pathological association which could be specific for SARS-CoV-2 infection and associated with poor fetal outcome; (2) Methods: We collected all the placental pathological examinations performed in Brest University Hospital (France) since the beginning of COVID-19 pandemic with a known maternal SARS-CoV-2 infection and a poor pregnancy outcome. In these cases, we described the pathological lesions and we searched for these lesions in a large series of placentas collected and examined in the same institution before the SARS-CoV-2 pandemic; (3) Results: Three cases with severe fetal outcome (tardive abortion, prematurity, neonatal death), from the first to the third trimesters of pregnancy, were included. The three cases showed features of massive and acute “placentitis triad” consisting in massive perivillous fibrin deposition, sub-acute intervillositis and trophoblastic necrosis. This association was not encountered in any of 8857 placentas analyzed during the period between 2002 and 2012 in our institution; (4) Conclusions: The “placentitis triad” appears to be specific for SARS-CoV-2 infection and, in case of massive and acute presentation, could result in poor fetal outcome.