Low risk of invasive lobular carcinoma of the breast in carriers of BRCA1 (hereditary breast and ovarian cancer) and TP53 (Li-Fraumeni syndrome) germline mutations

Co-regulator activity of Mediator of DNA Damage Checkpoint 1 (MDC1) is associated with DNA repair dysfunction and PARP inhibitor sensitivity in lobular carcinoma of the breast

Invasive lobular carcinoma of the breast (ILC) is typically estrogen receptor α (ER)-positive and presents with biomarkers of anti-estrogen sensitive disease, yet patients with ILC face particularly poor long-term outcomes with increased recurrence risk, suggesting endocrine response and ER function are unique in ILC. ER is co-regulated by the DNA repair protein Mediator of DNA Damage Checkpoint 1 (MDC1) specifically in ILC cells, driving distinct ER activity. However, this novel MDC1 activity is associated with dysfunctional canonical DNA repair activity by MDC1, but without typical features of DNA repair deficiency. To understand reciprocal activities of MDC1, we profiled the MDC1 interactome and found MDC1-associated proteins in ILC cells mirror a "BRCA-like" state lacking key homologous recombination (HR) proteins, consistent with HR dysfunction but distinct from classic "BRCAness". HR dysfunction in ILC cells is supported by single-cell transcriptome and DNA repair activity analyses, with DNA repair signaling and functional data, showing dysfunctional induction and resolution of HR. In parallel, ILC tumor data are consistent with a distinct form of HR dysfunction via impaired HR resolution, lacking BRCA-like genomic scarring but showing elevated signatures of PARP inhibitor sensitivity. We demonstrate this HR dysfunction can be exploited using PARP inhibition, and found that talazoparib treatment produced a durable growth suppression both in vitro and in multiple ILC xenografts in vivo. ILC-specific ER:MDC1 activity creates a new context for ER and MDC1 function in ILC, at the cost of a DNA repair dysfunction, which may be therapeutically targetable.

Upregulation of olfactory receptors and neuronal-associated genes highlights complex immune and neuronal dysregulation in Long COVID patients

A substantial portion of patients infected with SARS-CoV-2 experience prolonged complications, known as Long COVID (LC). A subset of these patients exhibits the most debilitating symptoms, similar to those defined in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). We performed bulk RNA sequencing (RNAseq) on the whole blood of LC with ME/CFS, at least 12 months post-onset of the acute disease, and compared them with controls. We found that LC patients had a distinct transcriptional profile compared to controls. Key findings include the upregulation of genes involved in immune dysregulation and neuronal development, such as Fezf2, BRINP2, HOXC12, MEIS2, ZFHX3, and RELN. These genes are linked to neuroinflammatory responses, cognitive impairments, and hematopoietic disturbances, suggesting ongoing neurological and immune disturbances in LC patients. RELN, encoding the Reelin protein, was notably elevated in LC patients, potentially serving as a biomarker for LC pathogenesis due to its role in inflammation and neuronal function. Immune cell analysis showed altered profiles in LC patients, with increased activated memory CD4 + T cells and neutrophils, and decreased regulatory T cells and NK cells, reflecting immune dysregulation. Changes in cytokine and chemokine expression further underscore the chronic inflammatory state in LC patients. Notably, a unique upregulation of olfactory receptors (ORs) suggest alternative roles for ORs in non-olfactory tissues. Pathway analysis revealed upregulation in ribosomal RNA processing, amino acid metabolism, protein synthesis, cell proliferation, DNA repair, and mitochondrial pathways, indicating heightened metabolic and immune demands. Conversely, downregulated pathways, such as VEGF signaling and TP53 activity, point to impaired tissue repair and cellular stress responses. Overall, our study underscores the complex interplay between immune and neuronal dysfunction in LC patients, providing insights into potential diagnostic biomarkers and therapeutic targets. Future research is needed to fully understand the roles and interactions of these genes in LC pathophysiology.

Characteristics and clinical outcomes of breast cancer in young BRCA carriers according to tumor histology

BACKGROUND

Young women with breast cancer (BC) have an increased chance of carrying germline BRCA pathogenic variants (PVs). Limited data exist on the prognostic impact of tumor histology (i.e. ductal versus lobular) in hereditary breast cancer.

METHODS

This multicenter retrospective cohort study included women aged ≤40 years with early-stage breast cancer diagnosed between January 2000 and December 2020 and known to carry germline PVs in BRCA1/2. Histology was locally assessed in each center. The Kaplan-Meier method and Cox regression analysis were used to assess disease-free survival and overall survival.

RESULTS

Of 4628 patients included from 78 centers worldwide, 3969 (86%) had pure ductal, 135 (3%) pure lobular, and 524 (11%) other histologies. Compared with ductal tumors, lobular tumors were more often grade 1/2 (57.7% versus 22.1%), stage III (29.6% versus 18.5%), and luminal A-like (42.2% versus 12.2%). Lobular tumors were more often associated with BRCA2 PVs (71.1% BRCA2), while ductal tumors were more often associated with BRCA1 PVs (65.7% BRCA1). Patients with lobular tumors more often had mastectomy (68.9% versus 58.3%), and less often received chemotherapy (83.7% versus 92.9%). With a median follow-up of 7.8 years, no significant differences were observed in disease-free survival (adjusted hazard ratio 1.01, 95% confidence interval 0.74-1.37) or overall survival (hazard ratio 0.96, 95% confidence interval 0.62-1.50) between patients with ductal versus lobular tumors. No significant survival differences were observed according to specific BRCA gene, breast cancer subtype, or body mass index.

CONCLUSIONS

In this large global cohort of young BRCA carriers with breast cancer, the incidence of pure lobular histology was low and associated with higher disease stage at diagnosis, luminal-like disease and BRCA2 PVs. Histology did not appear to impact prognosis.

Li-Fraumeni syndrome in Tunisian carriers with different and rare tumor phenotype: genotype-phenotype correlation

BACKGROUND

Li-Fraumeni syndrome (LFS) is a rare autosomal hereditary predisposition to multiples cancers, mainly affecting young individuals. It is characterized by a broad tumor spectrum. To our best knowledge, only one Tunisian study with a confirmed LFS was published.

METHODS

Our study focused on the clinical, histopathological and genetic results of two patients with rare tumor phenotype and tried to establish genotype-phenotype correlation. The clinical diagnosis was based on Chompret-Bonaiti criteria relative to LFS. Molecular study was assessed using Sanger sequencing of the hotspot germline variants of TP53 gene.

RESULTS

We report 2 Tunisian families fulfilling the clinical criteria of Chompret-Bonaiti. The tumor phenotype was bilateral breast cancer (BC) in 27-year-old woman and multiple tumors for the second proband, with an onset age of 14, 35 and 36 yo for osteosarcoma, BC and esophageal cancer respectively. Each of them had a rare histological type of breast cancer associated with LFS, phyllode tumor and intralobular carcinoma. Both patients had cancer family history. The molecular study showed deleterious heterozygous germline TP53 variants in each index case: The first had a well-known hotspot missense variation c.742C>T p.(R248W) with a rare histological association, explaining genotype phenotype correlation. The second case had a nonsense variation c.159G>A p.(W53*), rare worldwide, extending the phenotype spectrum in LFS. Immunohistochemistry study in tumor samples confirmed the lack of p53 protein expression.

CONCLUSIONS

Conclusively, germline TP53 testing is primordial in patients with a family history suggestive of LFS for clinical practice avoiding genotoxic treatments and adapting the surveillance. National database in LFS listing clinical and mutational data is important to set, particularly for variants rarely reported worldwide. Experience from different countries must be integrated to harmonize global protocols for cancer surveillance in LFS.

Germline Pathogenic Variants in Cancer Predisposition Genes Among Women With Invasive Lobular Carcinoma of the Breast

PURPOSE

To determine the contribution of germline pathogenic variants (PVs) in hereditary cancer testing panel genes to invasive lobular carcinoma (ILC) of the breast.

MATERIALS AND METHODS

The study included 2,999 women with ILC from a population-based cohort and 3,796 women with ILC undergoing clinical multigene panel testing (clinical cohort). Frequencies of germline PVs in breast cancer predisposition genes (ATM, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, PALB2, PTEN, RAD51C, RAD51D, and TP53) were compared between women with ILC and unaffected female controls and between women with ILC and infiltrating ductal carcinoma (IDC).

RESULTS

The frequency of PVs in breast cancer predisposition genes among women with ILC was 6.5% in the clinical cohort and 5.2% in the population-based cohort. In case-control analysis, CDH1 and BRCA2 PVs were associated with high risks of ILC (odds ratio [OR] > 4) and CHEK2, ATM, and PALB2 PVs were associated with moderate (OR = 2-4) risks. BRCA1 PVs and CHEK2 p.Ile157Thr were not associated with clinically relevant risks (OR < 2) of ILC. Compared with IDC, CDH1 PVs were > 10-fold enriched, whereas PVs in BRCA1 were substantially reduced in ILC.

CONCLUSION

The study establishes that PVs in ATM, BRCA2, CDH1, CHEK2, and PALB2 are associated with an increased risk of ILC, whereas BRCA1 PVs are not. The similar overall PV frequencies for ILC and IDC suggest that cancer histology should not influence the decision to proceed with genetic testing. Similar to IDC, multigene panel testing may be appropriate for women with ILC, but CDH1 should be specifically discussed because of low prevalence and gastric cancer risk.

Extended gene panel testing in lobular breast cancer

Purpose: Lobular breast cancer (LBC) accounts for ~ 15% of breast cancer. Here, we studied the frequency of pathogenic germline variants (PGVs) in an extended panel of genes in women affected with LBC. Methods: 302 women with LBC and 1567 without breast cancer were tested for BRCA1/2 PGVs. A subset of 134 LBC affected women who tested negative for BRCA1/2 PGVs underwent extended screening, including: ATM, CDH1, CHEK2, NBN, PALB2, PTEN, RAD50, RAD51D, and TP53.Results: 35 PGVs were identified in the group with LBC, of which 22 were in BRCA1/2. Ten actionable PGVs were identified in additional genes (ATM(4), CDH1(1), CHEK2(1), PALB2(2) and TP53(2)). Overall, PGVs in three genes conferred a significant increased risk for LBC. Odds ratios (ORs) were: BRCA1: OR = 13.17 (95%CI 2.83–66.38; P = 0.0017), BRCA2: OR = 10.33 (95%CI 4.58–23.95; P < 0.0001); and ATM: OR = 8.01 (95%CI 2.52–29.92; P = 0.0053). We did not detect an increased risk of LBC for PALB2, CDH1 or CHEK2. Conclusion: The overall PGV detection rate was 11.59%, with similar rates of BRCA1/2 (7.28%) PGVs as for other actionable PGVs (7.46%), indicating a benefit for extended panel genetic testing in LBC. We also report a previously unrecognised association of pathogenic variants in ATM with LBC.

OMICS insights into cancer histology; Metabolomics and proteomics approach

Metabolomics as a post-genomic research area comprising different analytical methods for small molecules analysis. One of the underlying applications of metabolomics technology for better disease diagnosis and prognosis is discovering the metabolic pathway differences between healthy individuals and patients. On the other hand, the other noteworthy applications of metabolomics include its effective role in biomarker screening for cancer detection, monitoring, and prediction. In other words, emerging of the metabolomics field can be hopeful to provide a suitable alternative for the common current cancer diagnostic methods especially histopathological tests. Indeed, cancer as a major global issue places a substantial burden on the health care system. Hence, proper management can be beneficial. In this respect, formalin-fixed paraffin-embedded tissue specimens (in histopathological tests) are considered as a valuable source for metabolomics investigations. Interestingly, formalin-fixed paraffin-embedded tissue specimens can provide informative data for cancer management. In general, using these specimens, determining the cancer stage, individual response to the different therapies, personalized risk prediction are possible and high-quality clinical services are the promise of OMICS technologies for cancer disease. However, considering all of these beneficial characteristics, there are still some limitations in this area that need to be addressed in order to optimize the metabolomics utilizations and advancement.