DNA and RFLP analysis. A) Hinf 1 restriction digestion (RFLP) of PCR products (C/C: 198 bp) were used to screen for C677T SNP genotype of MTHFR. The C677T MTHFR polymorphism creates a Hinf 1 cleavage site, yielding DNA fragment lengths of 175 bp and 23 bp in the presence of the variant T allele. The normal (HGF-1) and all three oral cancer cell lines (SCC25, SCC15, CAL27) were found to harbor wild type (C/C) genetic profiles; no heterozygotes (C/T) or homozygous mutants (T/T) were observed. B) DNA concentration and purity derived from absorbance readings at 260 and 280 nm revealed similar concentrations (821-895 ng/μL) and purity (1.76 - 1.92) from each cell line. C) PCR using control using GAPDH established similar band intensities from each cell line.