This oncogenic function of HOXB13 is thought to require activated ras, as HOXB13 promoted tumourgenesis in ovarian cancer cell lines containing genetic alterations in p53, myc and K-ras but not in cell lines containing genetic alterations in p53, myc and Akt. In this ras activated cell line, HOXB13 also conferred resistance to tamoxifen-mediated apoptosis suggesting a pro-survival role in ovarian cancer. The gene discussed is TP53; the disease is ovarian cancer.