You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Outcome", "Participant", "Intervention"].

Please return the output as a JSON object of the format: {"Participant" : ["patients with COPD", ...], "Intervention" : ["Atenolol", ...], "Outcome" : ["blood pressure", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Nonspecific and selective stimulation of the immune system in the treatment of carcinoma in humans . The experience of the Toronto General Hospital in the use of nonspecific stimulation of the immune system with bacille Calmette-Guérin ( BCG ) for the treatment of cancer of the gastrointestinal tract , malignant melanoma and breast cancer is described . The results are presented in terms of survival curves . The use of BCG administered intraperitoneally in a randomized study of patients with gastric , pancreatic and colorectal cancer proved of no benefit . On the other hand , when BCG was given orally in a randomized study of patients with resectable cancer of the colon and in nonrandomized consecutive studies of patients with malignant melanoma and stage IV carcinoma of the breast survival was increased . In a group of patients with advanced gastrointestinal cancer selective stimulation of the immune system with NED 137 produced a significant increase in survival when compared with the survival of historical controls ( the patients given BCG intraperitoneally along with 5-fluorouracil for gastrointestinal cancer ) . The results of these studies suggest the need for a more rational approach in manipulating the immune response that would combine chemotherapy with selective stimulation of the immune system .
{"Intervention": [], "Outcome": [], "Participant": []}