We investigate tumor suppressor TS) genes in cancer and how TS deficiencies lead to tumor formation and progression. We have characterized Inhibitor of Growth 4 ING4) TS in breast cancer, of which deficiency is correlated with metastatic and therapy-resistant tumors. We have defined ING4 as a transcriptional regulator that plays a critical role in tumor-immune modulation and hormone response. Ongoing studies include the molecular mechanism of ING4 and TSs in neuroblastoma and lung cancer.