The cytotoxic action of anticancer drugs can be potentiated by inhibiting DNA repair mechanisms. RAD51 is a crucial protein for genomic stability due to its critical role in the homologous recombination (HR) pathway. BRCA2 assists RAD51 fibrillation and defibrillation in the cytoplasm and nucleus and assists its nuclear transport. BRC4 is a peptide derived from the fourth BRC repeat of BRCA2, and it lacks the nuclear localization sequence. Here, we used BRC4 to (i) reverse RAD51 fibrillation; (ii) avoid the nuclear transport of RAD51; and (iii) inhibit HR and enhance the efficacy of chemotherapeutic treatments. Specifically, using static and dynamic light scattering, transmission electron microscopy, and microscale thermophoresis, we show that BRC4 eroded RAD51 fibrils from their termini through a “domino” mechanism and yielded monomeric RAD51 with a cumulative nanomolar affinity. Using cellular assays (BxPC-3, pancreatic cancer), we show that a myristoylated BRC4 (designed for a more efficient cell entry) abolished the formation of nuclear RAD51 foci. The present study provides a molecular description of RAD51 defibrillation, an essential step in BRCA2-mediated homologous recombination and DNA repair.

TERT gene mutations play critical roles in tumor progression and have important implications in several solid tumors, including thyroid carcinoma. This study aimed to evaluate the association between TERT promoter mutations and histology and clinical features of thyroid carcinoma (TC). We performed an up-to-date systematic review and a comprehensive meta-analysis. Systematic searches were made on MEDLINE (via Pubmed) databases using relevant keywords, and articles published until November 1st, 2024 were selected. A total of 54 studies and 17'021 samples are included in the meta-analysis. Relevant data for the meta-analysis was extracted, and for statistical analysis, chi-square calculation was used. Thyroid carcinomas with the highest frequency of TERT mutations are Anaplastic thyroid carcinoma (55.8 %) and Diffuse sclerosing variant of papillary thyroid carcinoma (60.4 %). No TERT mutations founds in Benign neoplasm, NIFTP and Medullary thyroid carcinoma. Mutations with the highest frequency is c.-124C>T (chr5:1295228 - C228T). TERT mutations are statistically correlated with Stage III&IV, presence of metastasis, overall survival, recurrence and radioiodine-refractory. TERT mutation plays a crucial role as a prognostic biomarker with tumor aggressiveness. Thus, in clinical practice, mutational status assessment of the TERT promoter should be considered for accurate prognostic stratification of TCs.