The present invention relates to a use of NKX6.3 for prediction of cancer occurrence and early diagnosis of cancer and as a therapeutic agent for cancer and, more specifically, to a use of NKX6.3 for prediction of cancer occurrence and early diagnosis of cancer on the basis of the expression level of NKX6.3 protein, the expression level of mRNA and the number of DNA copies, and for prevention and treatment of cancer by administrating an NKX6.3 protein or gene. The NKX6.3 in accordance with the present invention can be used as a diagnostic composition for early diagnosis of cancer because the activity or expression thereof is inhibited in a cancer cell. In addition, the NKX6.3 exerts the functions of inhibiting the survival and proliferation of cancer cells and inducing apoptosis when the expression thereof is induced, and thus can be usefully used as a composition for anti-cancer treatment.
