Investigating EGFR, BRAF, and RAS Mutations in Oral and Cutaneous Squamous Cell Neoplasms: A Preliminary Report on Romanian Patients
Authors:   Immunology Department, "Victor Babes" National Institute of Pathology, Bucharest, Romania
Faculty of Biology, University of Bucharest, Bucharest, Romania, Dobre Elena G. , Căruntu Ana ,   Department of Oral and Maxillofacial Surgery, "Carol Davila" Central Military Emergency Hospital, Bucharest, Romania
Faculty of Dental Medicine, "Titu Maiorescu" University, Bucharest, Romania, Munteanu Adriana N. ,   Immunology Department, "Victor Babes" National Institute of Pathology, Bucharest, Romania
Faculty of Biology, University of Bucharest, Bucharest, Romania, Surcel Mihaela ,   Immunology Department, "Victor Babes" National Institute of Pathology, Bucharest, Romania, Constantin Carolina ,   Immunology Department, "Victor Babes" National Institute of Pathology, Bucharest, Romania
Faculty of Biology, University of Bucharest, Bucharest, Romania
Department of Pathology, Colentina University Hospital, Bucharest, Romania, Căruntu Constantin ,   Department of Physiology, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
Department of Dermatology, "Prof. N.C. Paulescu" National Institute of Diabetes, Nutrition and Metabolic Diseases, Bucharest, Romania, Scheau Cristian ,   Department of Physiology, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
Department of Radiology and Medical Imaging, “Foisor” Clinical Hospital of Orthopaedics, Traumatology and Osteoarticular TB, Bucharest, Romania, Neagu Monica ,   Immunology Department, "Victor Babes" National Institute of Pathology, Bucharest, Romania
Faculty of Biology, University of Bucharest, Bucharest, Romania
Department of Pathology, Colentina University Hospital, Bucharest, Romania
Published: March 2024

Background: Head and neck cancers, and particularly, oral cancers have a complex pathogenesis that includes genetic
mutations and epigenetic alterations which interfere with cellular signaling and can trigger tumor development. The purpose of
this study was to reveal whether low-frequency hotspot mutations may be detected in a study lot with histopathological evidence
of squamous cell carcinoma (SCC) of the oral mucosa and skin of the head and neck. Methods: Tumor biopsies from treatment
naïve patients were tested for BRAF V600, NRAS G12/G13, NRAS Q61, KRAS Q61 mutations, and EGFR exon 19 deletions (Ex19Del)
using droplet digital PCR (ddPCR). The tumors were also analyzed for EGFR T790M mutations by RT-PCR, using a CE-IVD validated
kit, with a limit of detection of 0.05%. Results: None of the examined cases exhibited NRAS G12/G13, NRAS Q61, KRAS Q61, BRAF
V600, or EGFR T790M mutations, indicating that these alterations are rare events in SCC pathogenesis. Interestingly, among the
12 specimens tested by ddPCR for EGFR Ex19Del, an HPV-negative cSCC tumor occurring in the parotid region tested positive for
this drug-sensitizing mutation, offering unexplored therapeutic perspectives to the patient from whom it was collected.
Conclusions: Our study highlights the important clinical implications of detecting low-frequency hotspot mutations in tumor
biopsies by ddPCR. We believe that the ddPCR-assisted analysis of these mutations in larger SCC cohorts may provide us with
mechanistic insights regarding their role in SCC pathogenesis and guide the development of novel therapeutic strategies for this
problematic disease.