Methods: In this study, five salivary samples were collected from each group of the normal subjects, pre-oral squamous cell carcinoma and oral squamous cell carcinoma patients from Oral Cancer Research and Coordinating Centre (OCRCC) of University of Malaya, Malaysia. The genomic DNA were extracted and the exon 4 region within the p53 gene were amplified with sensitive mutation specific polymerase chain reactions (PCRs) followed by DNA purification and sequence analysis sebsequently.
Results: From the reams of sequencing chromatograms indicated the PCR products from these salivary samples of normal subjects showed 100% match with normal reference. In the pre-oral squamous cell carcinoma showed 40% of normal p53 sequence, 40 % of single nucleotide polymorphism (SNP) and 20% of substitution of G to C. Whereas the sequencing chromatograms of oral squamous cell carcinoma showed 40% of substitutions of G to C and 60% of SNP.
Conclusions: Our study demonstrated the single base substitution of G to C mutation and SNP of p53 gene in most of oral squamous cell carcinoma patients. We concluded that single base substitution of mutations and SNP in p53 gene can be detected by using direct sequencing assay.