Biomedical subjects

Nathalie Cassoux

Publications and source records attributed to Nathalie Cassoux.

3 recordsLinked to original sources

PubMed2026

Prevalence of the Predisposing Gene MBD4 for Uveal Melanoma.

IMPORTANCE: MBD4 monoallelic germline pathogenic and likely pathogenic variants have recently been identified as predisposing to uveal melanoma, a rare primary intraocular tumor, with an estimated 9.15-fold increased risk of developing the disease for pathogenic variant carriers. OBJECTIVE: To assess the risk of developing uveal melanoma for carriers of the MBD4 monoallelic germline pathogenic variant. DESIGN, SETTING, AND PARTICIPANTS: In a case series involving 896 individuals, including 319 who were previously evaluated, germline target-sequencing of MBD4 was offered to every new patient with uveal melanoma at Curie Institute from February 2021 to September 2025. Non-Finnish European participants from the Genome Aggregation Database were used as a reference population. EXPOSURE: Diagnosis of uveal melanoma genetic predisposition. MAIN OUTCOMES AND MEASURES: Prevalence of MBD4 variants. RESULTS: A total of 23 of 896 patients were identified as carrying an MBD4 germline pathogenic or likely pathogenic variant, corresponding to a relative risk of 31.44 (95% CI, 18.18-53.00) of developing uveal melanoma compared with the general population (2-sided Fisher exact test, P < .001). CONCLUSIONS AND RELEVANCE: These findings confirm that MBD4 is an important predisposing gene to uveal melanoma in the French population. This reinforces a strategy of broad patient screening given the therapeutic implications and the consequences of genetic counseling.

Humans↗

PubMed2025

A functional assay to classify RB1 variants of uncertain significance.

PURPOSE: The RB1 gene encodes the retinoblastoma protein (pRB) playing a major role in cell cycle control, particularly by its interaction with E2F transcription factors. Familial forms of retinoblastoma are caused by germline pathogenic variants in the RB1 gene predisposing to retinoblastoma and other tumors. By analyzing the RB1 gene in patients with retinoblastoma, we found that missense variants often remain variants of uncertain significance (VUS). METHODS: To classify RB1 VUS, we developed a functional assay evaluating their impact on the ability of pRB to inhibit the activity of the E2F1 promoter, with a luciferase reporter gene. A set of 14 pathogenic/likely pathogenic and benign/likely benign RB1 variants was used for validation. RESULTS: We tested 16 VUS detected in patients with retinoblastoma and found that 9 VUS reduced the ability of pRB to inhibit E2F1 promoter. Among them, the (RB1) c.2263T>G p.(Phe755Val) variant showed a reduced level of pRB on Western blot, suggesting a defect in pRB stability. By applying the criterion PS3_moderate of the American College of Medical Genetics and Genomics/Association for Molecular Pathology classification to this functional assay, 5 of the 9 VUS with functional impact could be classified as likely pathogenic. CONCLUSION: This functional assay can improve the molecular diagnosis of retinoblastoma predisposition by a better determination of pathogenic/likely pathogenic RB1 variants.

Humans↗

PubMed2025

Uveal Melanoma and the Lynch Syndrome Tumor Spectrum.

IMPORTANCE: To date, no environmental factors and few therapeutic options are known for uveal melanoma (UM), the most common malignant intraocular primary tumor in adults. Identification of new predisposition factors could lead to better monitoring and possibly improved treatments of patients with UM. OBJECTIVE: To identify new genetic alterations predisposing for UM. DESIGN, SETTING, AND PARTICIPANTS: This was a prospective cohort study conducted at Institut Curie in Paris, France, among 381 consecutive patients diagnosed with UM between July 2021 and February 2023. UM was diagnosed clinically by ophthalmologists, and a senior pathologist confirmed the diagnosis when tumor or biopsy was available. All participants received genetic counseling and consented to extended genetic testing. A panel of 122 genes predisposing to cancer were analyzed by targeted sequencing on germline DNA from these patients. MAIN OUTCOMES AND MEASURES: Frequency of pathogenic variants (PVs) in genes from a targeted panel, with classification of germline PVs done according to the American College of Medical Genetics and Genomics guidelines and the French Unicancer Genetics Group. RESULTS: A total of 79 PVs were identified in 70 participants (41 female and 29 male; mean [SD] age, 60.6 [15.3] years). Among them, 21 were found in clinically relevant genes, with an enrichment in the mismatch repair (MMR) genes, involved in Lynch syndrome, a frequent predisposition to colon and endometrial cancers. This finding suggested MMR germline PVs could also predispose to UM. One tumor was available from a participant carrying a MLH1 germline PV. The tumor exhibited a monosomy 3 with loss of the wild-type allele of MLH1, located on chromosome 3. Loss of expression of MLH1 was observed by immunohistochemistry, and MMR variant signatures SBS6, ID1, and ID2 were identified from the whole-genome sequencing of this tumor, supporting the possibility that MLH1 contributes to the oncogenesis of this UM. CONCLUSIONS AND RELEVANCE: This prospective germline study on patients with UM provided evidence supporting the notion that MMR germline alterations are enriched among patients with UM and may contribute to oncogenesis of UM, and that UM may therefore be a rare tumor manifestation of Lynch syndrome.

Humans↗