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: ["AnatomicalEntity"].

Please return the output as a JSON object of the format: {"AnatomicalEntity": ["tumor cells", ...]}. 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:

The learning curve: the advantages and disadvantages in the use of focus groups as a method of data collection.
Focus groups are not simply a discussion between people, but are focused interviews exploring interactions between participants. In this paper, Ian Mansell, Glynis Bennett, Ruth Northway, Donna Mead and Laurie Moseley explore the complexities and practicalities of using focus groups in research, with reference to a study of palliative care services.
{"AnatomicalEntity": []}