In KAT-18 cells, a primary culture of anaplastic thyroid cancer, a mutant p53 that harbors a gain of mutation, i.e., TP53G199V missense mutation, affected STAT3 expression status and mediated anti-apoptotic function by transcriptionally upregulating STAT3 [100]. Here, STAT3 is linked to thyroid gland undifferentiated (anaplastic) carcinoma.