Reliable detection of p53 aberrations in squamous cell carcinomas of the head and neck requires transcript analysis of the entire coding region.

Abstract

Aberrations of the p53 tumor suppressor gene are common events in squamous cell carcinomas of the head and neck (SCCHN). However, reported frequencies range considerably, and the predictive value of aberrant p53 is continuing to be an issue of controversy. These inconsistencies are possibly caused by methodical limitations. In cell lines established from 23 SCCHN, we performed sequence analysis of p53 mRNA and genomic DNA, as well as protein detection using immunohistochemistry and Western blotting. Of the 23 SCCHN, 21 (91%) tumors have aberrant or no p53, including four aberrations (19%) located outside the usually examined exons 5 to 9. A second allele is present in 11, and the respective transcript in 4 tumors. Expression of protein could be detected in only 12 of the 21 p53 aberrant tumors (57%). Depending on the methodical approach applied, a considerable number of SCCHN may be misclassified regarding their p53 status.