Figure 4.

Heterogeneous p53 status in tumors. While some cancers retain a WT TP53 gene, mutations in TP53 occur during the development of many cancers, leading to expansion of clones of tumor cells that express no p53 or a mutant p53 protein among the WT p53-expressing cells. In some tumors, this heterogeneity of p53 expression persists, but most cancers tend to become clonal for cells carrying the TP53 mutation, leading to genetic homozygosity with respect to TP53. However, signals that drive WT p53 into a pseudomutant conformation, or changes in adhesion characteristics within the tumor that result in loss of mutant p53 protein expression, can result in heterogeneity in p53 expression within a tumor that is clonal for the TP53 gene.