Sensitive detection of p53 mutation: Analysis by direct sequencing and multisequence analysis

In a wide variety of tumors. p53 mutations may have prognostic and diagnost ic value. However. mutational screening methods often are restricted to the core domain and. therefore, do not detect all mutations. We improved exist ing sequencing-based mutation analysis methods consisting of direct sequenc ing of all exons of the p53 gene and RNA. Multisequence analysis software w as developed and applied to increase the sensitivity of mutation identifica tion. Multisequence analysis compares a large number of sequences and ident ifies profiles with additional small peaks, potentially indicating a mutati on. Concordance between blood and tumor sequences indicates polymorphism, w hereas discordance indicates a mutation. We could detect mutations with a l imit of approximately 5% to 10% mutated DNA. In our ongoing studies, we app lied sequencing-based mutation analysis for more than 50 patients with head and neck squamous cell carcinoma and identified mutations in more than 95% of all tumors. We encountered some differences between the previously publ ished reference p53 sequence and all our sequences and identified polymorph ism in six regions.