Hydrocortisone dependency of breast cancer was studied using incubation method: tumor slice, cortisol and (32)P were incubated. Adequate cortisol in the incubation medium was 5μg/0.5ml with 50mg tumor slice. Cortisol dependent breast cancer patients had poor prognosis, on the contrary, cortisol independent breast cancer patients had favarable prognosis and longer survival even if recurred.