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: ["RNA", "CellLine", "Protein", "DNA", "CellType"].

Please return the output as a JSON object of the format: {"DNA" : ["TAL1", ...], "RNA": ["mRNAs", ...], "CellLine": ["T cells", ...], "CellType": ["monocytes", ...], "Protein": ["IL-2", ...]}. 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:

[ Changes in leucocytic estrogen receptor levels in patients with gynecomastia ] The number of estrogen receptor (ER) in human peripheral leucocytes in 13 men with gynecomastia were measured by radioligand binding method. The results were compared with those of 13 sex-and age-matched healthy subjects. It was found that the number of ER in leucocytes was significantly increased in gynecomastia (Rs of leucocytes were 1054 + /-254 sites / cell). It suggested that increase of ER levels play an important role in the pathogenesis of gynecomastia.
{"CellLine": [], "CellType": ["leucocytes", "human peripheral leucocytes"], "DNA": [], "Protein": ["estrogen receptor (ER)", "leucocytic estrogen receptor", "ER", "estrogen receptor"], "RNA": []}