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IntroductionThe prevalence of germline pathogenic/likely pathogenic variants (P/LP) in high and moderate penetrance (HMP) genes is approximately 7%–10% among breast cancer (BC) patients. The prevalence and spectrum of BC P/LP variants are affected by several factors. There are limited genetic data from Brazilian patients with BC.MethodsThis is a retrospective cross-sectional study that aims to evaluate the germline profile of P/LP variants in 13 HMP BC genes (BRCA1, BRCA2, PALB2, TP53, CDH1, NF1, PTEN, STK11, CHEK2, ATM, BARD1, RAD51C, and RAD51D) in patients diagnosed with BC in Brazil. All patients were tested using multigene NGS panels covering from 35 to 105 genes. Primary endpoint was the prevalence of P/LP variants in BRCA1/2 and in other HMP genes. Secondary endpoints were stratified analyses according to age and BC subtype.ResultsThis cohort involved 2,208 patients with BC from 2019 to 2023. Most patients (79.7%) were from Southeastern Brazil. The median age at genetic testing was 47 years, and most patients (59.4%) were ≤50 years. The BC subtype was available in 641 cases: 264 patients (41.2%) were HR+/HER2−, 116 (18.1%) were HER2+, and 261 (40.7%) had triple-negative breast cancer (TNBC). Overall, 215 (9.7%) had a P/LP in HMP genes, including 5.8% in BRCA1/2. The most frequent variants were found in BRCA2, BRCA1, and TP53. The founder variant R337H accounted for 79% of all TP53 pathogenic variants, representing 1% of the overall population. Deleterious variants in BRCA1/2 were more common in patients ≤50 years (7.7%) and TNBC (10.7%). In other HMP BC genes, the prevalence of P/LP variants did not significantly vary according to age and BC molecular subtype. The overall VUS rate in HMP genes was 19.6%.ConclusionIn Brazil, the epidemiology of deleterious variants in HMP is comparable to published US and EU cohorts. The Brazilian TP53 R337H is a prevalent variant in BC patients. Deleterious BRCA1/2 variants vary according to age and BC subtype. Our study gives a broader understanding of BC risk genes and has opened doors to optimized testing and surveillance strategies in Brazil.

PURPOSETissue inadequacy and operational challenges may limit lung cancer comprehensive biomarker testing. Here, we describe the initial implementation of a tailored tissue molecular journey at Oncoclínicas Precision Medicine Laboratory in Brazil, which includes fast-track (FT) non–next-generation sequencing (NGS) assays combined with a broad NGS panel.METHODSFrom 2021 to 2023, all nonsquamous lung cancer samples eligible for the patient support program “Lung Mapping Consortium” at Oncoclínicas & Co were evaluated using the FT panel (immunohistochemistry for PD-L1 and anaplastic lymphoma kinase [ALK], polymerase chain reaction for EGFR and BRAF, and fluorescence in situ hybridization for ROS1) plus a broad DNA and RNA sequencing panel of 180 genes (custom ARCHER panel).RESULTSFrom 1,272 samples received by the laboratory, 3% had no tissue for any molecular testing, 20% was not eligible for broad NGS panel as per pathologist assessment (tumor purity and quantity), additional 12% did not reach presequencing analytical thresholds (nucleic acid quantity and/or quality), and 3% had postsequencing failure. Most frequent alterations were KRAS mutations (28.4%, KRASG12C 9.7%), EGFR mutations (23.6%, exon20 insertions 2.9%), ALK fusions (6.4%), MET exon 14 skipping (4.4%), ERBB2 mutations (3.4%), ROS1 fusions (3.1%), and BRAFV600E (1.9%). In 35% of the samples, FT non-NGS tests were the only molecular diagnostics: EGFR mutations (14%), ALK fusions (4.4%), ROS1 fusions (1.8%), and BRAFV600E (0.7%). Overall, high PD-L1 expression (≥50%) was found in 12.3%.CONCLUSIONThis study provides data on the molecular epidemiology of lung adenocarcinoma in Brazil, confirming high prevalence of EGFR mutations, ALK fusions, and MET exon 14 skipping alteration. Biomarker detection is largely affected by biospecimen collection and processing, with one third of the patients eligible for non-NGS testing only, which presents reduced coverage and sensitivity for actionable drivers.

Alternative protein-coding transcripts of the RASSF1 gene have been associated with dual functions in human cancer: while RASSF1C isoform has oncogenic properties, RASSF1A is a tumour suppressor frequently silenced by hypermethylation. Recently, the antisense long non-coding RNA RASSF1 (ANRASSF1) was implicated in a locus-specific mechanism for the RASSF1A epigenetic repression mediated by PRC2 (Polycomb Repressive Complex 2). Here, we evaluated the methylation patterns of the promoter regions of RASSF1A and RASSF1C and the expression levels of these RASSF1 transcripts in breast cancer and breast cancer cell lines. As expected, RASSF1C remained unmethylated and RASSF1A was hypermethylated at high frequencies in 75 primary breast cancers, and also in a panel of three mammary epithelial cells (MEC) and 10 breast cancer cell lines (BCC). Although RASSF1C was expressed in all cell lines, only two of them expressed the transcript RASSF1A. ANRASSF1 expression levels were increased in six BCCs. In vitro induced demethylation with 5-Aza-2ʹ-deoxicytydine (5-Aza-dC) resulted in up-regulation of RASSF1A and an inverse correlation with ANRASSF1 relative abundance in BCCs. However, increased levels of both transcripts were observed in two MECs (184A1 and MCF10A) after treatment with 5-Aza-dC. Overall, these findings indicate that ANRASSF1 is differentially expressed in MECs and BCCs. The lncRNA ANRASSF1 provides new perspectives as a therapeutic target for locus-specific regulation of RASSF1A.

Abstract: Potentially neurogenic areas were initially identified by incorporation of bromodeoxyuridine (BrdU) in cells underlying the subventricular zone (SVZ) of the lateral ventricles wall, hippocampus and olfactory bulbs of newborn guinea pigs. Neural precursors from the SVZ were cultured in suspension, generating neurospheres (NSFs), which, upon dissociation were able to generate new NSFs. Upon culture in the absence of growth factors, cells dissociated from NSFs displayed evidence for neural differentiation, giving rise to cells from neural lineage. Flow cytometry analysis for of NSFs-derived cells after differentiation revealed approximately 13.3% nestin positive, 5.5% Beta-III-tubulin positive, 9% GFAP positive and 7.8% mGalC positive. Functional assays by measurement of calcium influx upon gamma butiric amino acid (GABA) and glutamate stimuli, revealed stimulation in differentiated cells, an indicator of neuronal differentiation. The ability of guinea pig SVZ cells to originate functional neurons in vitro is promising for research and towards a future use of neural stem cells in the therapy of neurological disorders.