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:

Angiogenesis: initiation and control.
From in vivo experiments using new methods such as the rabbit cornea, it is now becoming clear that the growth of a capillary involves an ordered sequence of events that includes lysis of the basement membrane of a parent venule, directional migration of capillary endothelial cells toward the angiogenic stimulus, lumen formation, development of branches, and anastomosis of the tip of one tube with another to form a loop. It is also clear that diffusible angiogenic stimuli can be released not only from most solid tumors, but also from at least three non-neoplastic cells. These include activated macrophages, sensitized lymphocytes, and adipocytes. Other normal tissues can also stimulate angiogenesis, but the type of cell giving rise to the angiogenic stimulus is unknown, and the period of angiogenic stimulation is brief. With the recent ability to clone capillary endothelial cells and to carry them in long-term culture, it has been possible to further delineate the mechanism of capillary growth. In vitro studies have shown that the mast cell seems to behave as a helper cell for capillary endothelial cells, in some way speeding up their rate of directional migration. At this writing, heparin appears to be the principal mast cell factor responsible for this effect on capillary endothelial cells. One theoretical possibility is that mast cells may prepare the matrix, perhaps by slow release of heparin, so that capillary sprouts can more easily move through it toward their angiogenic target. While the study of angiogenesis as a phenomenon is still in an early phase, it has become possible, by using a combination of in vitro and in vivo techniques, to more thoroughly understand the initiation and control of capillary growth.
{"AnatomicalEntity": ["lymphocytes", "tissues", "capillary endothelial cells", "solid tumors", "venule", "helper cell", "basement membrane", "capillary", "cell", "matrix", "tube", "cornea", "lumen", "mast cell", "branches", "mast cells", "adipocytes", "macrophages", "non-neoplastic cells", "capillary sprouts"]}