Formalin-fixed paraffin-embedded tissues were stained by immunohistochemistry for p53, MDM2 and Ki-67 proteins. Results: H-ras mutations were detected in 3 cases (16.7%), including one insertion of three nucleotide (GGC) between codons 10 and 11 resulting in in-frame insertion of glycine (10Gly11), one missense point mutation in codon 12 (GGC>AGC) and one missense point mutation in codon 13 (GGT>CGT) resulting in amino acid changes.