Investigation of Oncogenic Gene Mutation and Associated Protein Expression in Ameloblastic Carcinoma

Objective: This study aimed to investigate gene mutations in ameloblastic carcinoma (AC) including BRAF, KRAS, and PIK3CA, along with associated protein expressions of BRAF V600E, p-ERK1/2, and p-mTOR, which represent activation of MAPK/ERK and PI3K/mTOR pathways, respectively. Materials and Methods: Ten formalin-fixed, paraffin-embedded AC tissue samples were collected. Tumor area samples were manually micro-dissected for DNA extraction. All samples then underwent gene amplification using polymerase chain reaction and were subsequently sent for DNA sequencing. The investigation of protein expressions was assessed using immunohistochemistry. Results: Heterozygous mutations in BRAF, KRAS, and PIK3CA were observed in 40.0%, 30.0%, and 30.0% of AC cases, respectively. Notably, 75.0% of BRAF-mutated cases (3/4) co-harbored either KRAS or PIK3CA mutations. Immunohistochemical analysis revealed BRAF V600E expression in 40.0% of cases. AC also expressed mild immunostaining for p-ERK1/2 (mean IRS ± SD; 2.50 ± 2.526) and moderate immunostaining for p-mTOR (mean IRS ± SD; 7.62 ± 2.869), within both the cytoplasm and nucleus of the tumor cells. Conclusion: The presence of these oncogenic gene mutations and protein expressions suggests that MAPK/ERK and PI3K/mTOR pathways may contribute to AC pathogenesis. However, further studies with larger sample sizes are needed to confirm these findings.