Akademik Veri Yönetim Sistemi
International Hereditary Cancers Congress, Antalya, Türkiye, 6 - 08 Şubat 2025, cilt.36, ss.32, (Özet Bildiri)
Introduction: Retinoblastoma (RB) is a malignant neoplasm of the retina, predominantly affecting pediatric patients. A substantial proportion of cases are hereditary and are caused by heterozygous variants in the RB1 gene. Objectives: This case study aimed to evaluate the correlation between somatic genetic variants in RB patients and their associated clinical manifestations. Methods: A 9-month-old boy with trilateral retinoblastoma was evaluated by next-generation sequencing (NGS) technology for the RB1 gene on peripheral blood samples and tumor tissue. Results: The peripheral blood analysis detected a pathogenic RB1 variant with a very low variant allele frequency (VAF) of 6%. In contrast, analysis of tumor tissue [formalin-fixed paraffin-embedded (FFPE)] demonstrated a significantly higher VAF of 62%, consistent with postzygotic somatic mosaicism. As expected, there was also a second pathogenic variant in the patient's tumor tissue. Segregation analysis revealed that the variants was de novo. Conclusion: The findings underscore the critical importance of analyzing tumor tissue alongside low-frequency variants in blood samples. The integration of peripheral and tumor tissue analysis is essential to accurately detect mosaic variants, providing valuable insights for tailoring patient care. Such efforts are crucial for guiding treatment decisions, genetic counseling, and assessing familial risk. Keywords: RB1, Retinoblastoma, Somatic Mosaicism