MDM4 Isoform Expression in Melanoma Supports an Oncogenic Role for MDM4-A

Figure 7

Model of melanomagenesis with the timeline of MDM2/4/p53 changes. Throughout progression from normal skin to metastatic disease, most cases retain wild-type p53 and demonstrate normal splicing and normal copy numbers of MDM2. In contrast, changes in MDM4 splicing are already in place in melanocytic nevi. MDM4 tends to be amplified in melanomas, and the profile of mRNA isoforms expressed is dramatically different from normal skin. This includes relatively high levels of MDM4-A.