It is now known that mutant p53 proteins not only lost their transcriptional function (loss of function), but also commonly obtain new function (gain of function).7 For instance, p53-R175H exhibits a gain of oncogenic function in driving cell migration and invasion.4, 8 Studies from animal models have confirmed that mice bearing a mutant p53 allele show more aggressive and metastatic tumor than p53 null.9, 10, 11 In human cancers, mutant p53 expression has been linked to poorer prognosis.12 The gene discussed is TP53; the disease is metastatic neoplasm.