a: Mutations inCDK4detected by PCR-SSCP analysis in head and neck cancer samples, digital image of an ethidium bromide stained 8% non denaturing polyacrylamide gel showing band pattern. Arrow head indicates change in band shift. C represents HNC cases and N represents normal samples. b: Sequencing electropherogram of mutations in CDK4: (A) Missense g5051G > C mutation, (CM994495) in exon 2 showing G to C substitution resulting in change of DNA sequences from AGC to ACC encoding amino acid threonine instead of serine, (B) Missense mutation, g5095G > C (Novel) in exon 2 showing G to C substitution resulting in change of DNA sequence from GAG to CAG encoding the amino acid glutamine instead of glutamate, (C) Missense mutations, g5906C > A, g5907C > G in exon 5 changing the DNA sequence from CCT to AGT encoding the amino acid serine instead of proline, (D) Frame shift mutation in 3′UTR as a result of insertion of nucleotide G, (g7121_7122insG), (E) Frame shift mutation in 3′UTR as a result of deletion of nucleotide G (g7143delG), (F) Missense mutation g7320A > C and frameshift mutation g7321_23delTGA in exon 7.