RARγ is oncogenic in many cancers including some cases of acute myeloid leukemia, cholangiocarcinoma, and colorectal, gastric, head and neck, hepatocellular, ovarian, pancreatic, prostate, renal, and thyroid cancers (reviewed in [1]). From immuno-histological studies, high level expression was seen for tissue samples from patients with cholangiocarcinoma with lymph node metastases, stage III–IV ovarian cancer, pancreatic cancer, and high-grade prostate cancer. High expression of RARγ in colorectal cancer correlated with the expression of multidrug resistance 1 and a reduced sensitivity to chemotherapeutics. For thyroid cancer, high expression has been linked to the promotion of tumor invasiveness and metastasis. Examination of the survival curves for patients regarding the level of expression of RARγ has shown that high ex-pression is a predictor of poor overall survival outcomes for patients with AML, cholangiocarcinoma, and gastric, ovarian and pancreatic cancers. Active RARγ enhances cell proliferation and plays a role in the maintenance of stem cells. Both these roles are commensurate with RARγhaving a role in aggressive cancer.