452 Molecular and histopathologic profiling of melanocytic nevi in patients with RASopathies

Melanocytic nevi are among the most common benign human neoplasms and mimics, risk factors, potential precursors for melanoma. Many drivers of melanoma tumor progression have been identified, such as somatic mutations in RAS pathway genes. It is also known that germline genetic variants influence nevus count RASopathy patients. However, why develop certain undergo melanomagenesis remains largely unknown. This project aims to evaluate role nevogenesis by studying individuals with RASopathies, specifically cardio-facio-cutaneous (CFC) syndrome Costello (CS) corresponding normal tissue were collected or already biopsy slides retrieved from The samples underwent histopathological analysis, if material was available, immunohistochemistry screening BRAF V600E whole-genome sequencing. Eight melanocytic 5 patients included (ages 25, 80% female, 20% male). Two had CFC 3 CS. Histopathological analysis revealed 4 compound nevi, intradermal 1 junctional nevus. Dysplastic features noted one Immunohistochemistry performed on two positive patient. Sequencing this patient a p.V600E driver mutation p.E501G mutation. In CS nevus, HRAS p.G12C but no detected. utilizes combination histopathology whole-exome sequencing investigate pathway. study will expand our knowledge RASopathies regulation development nevi. Analyses additional required forthcoming.