ASSESSMENT OF SEQUENCE-BASED P53 GENE ANALYSIS IN HUMAN BREAST-CANCER- MESSENGER-RNA IN COMPARISON WITH GENOMIC DNA TARGETS

The high prevalence of p53 mutations in human cancers and the suggesti on from several groups that the presence or absence of p53 mutations m ight have both prognostic and therapeutic consequences point to the im portance of optimal methods for p53 determination. Several strategies exploring this have been described, based either on mRNA or genomic DN A as a template. However, no comparative study on the reliability of t he two templates has been performed. The principal aim of this study w as to study the concordance of RNA-and DNA-based direct sequencing met hods in detecting p53 mutations in breast tumors. In 100 tumors, 22 mu tations were detected by both methods. Furthermore, one stop mutation, two splice-site mutations, and one intron alteration were found only by genomic sequencing. In addition, the comparative study suggests tha t cells with missense mutations have increased steady-state concentrat ions of p53-specific mRNA, in contrast to cells with a gene encoding a truncated protein.