Background
This study is focused on the identification of gene mutations in H-ras which are probably associated with tumor recurrence in oral squamous cell carcinoma (OSCC) following conventional therapy.
Conclusion
These data may suggest that regardless of the causes and factors involved, Gly12Ala (G6266A) is associated with recurrence in high-grade OSCC tumors.
Methods
Surgically removed biopsies from OSCC patients without recurrence (n = 43) and biopsies from recurrent cases (n = 19) were analyzed. Also, gingival tissues (n = 5) from normal individuals were processed and considered as control. DNA was extracted and amplified using primers for exons 1 and 2 for the H-ras gene, and then DNA products were analyzed using Sanger's sequencing technique. Besides, H-ras expression was compared in samples by immunostaining (IHC), using anti-ras antibody.
Results
Demographic data show that smoking habit in patients and recurrent tumors was ~ 44.1 and 78%, respectively. The major site of malignancy was tongue tissue (40-60%). The rate of pathological stage III/IV were 41.8 and 100% in primary tumors and recurrence malignancy respectively. The sequencing data showed that a specific mutation in H-ras gene, Gly12Ala (G6266A) in recurrence samples and primary cases was detected in ~ 66.6% and 10% respectively. Accumulation of H-ras protein in tissues was relatively high scores (> 5) in both primary and recurrence tumors. The H-ras mutation detected was associated with increased level of H-ras protein accumulated in the malignant cells (IHC data).