The present disclosure, a device for collecting and processing a sample of body fluid containing cells, solutions and methods, (collecting other fluids, including similarly toxic and / or hazardous materials / fluids, and treatment and / or analysis of aspect) for. Furthermore, the present disclosure relates generally to the functional genomic research, as well as for cell analysis, isolation and for the storage of derived cells from the saliva and other body fluids (eg, urine). Some embodiments relates to a device for collecting body fluid, in some embodiments, includes an internal space closed the lid to hold the sample preservation solution and mated to the tube, (closed) constituting the sampling device If you want to, including 2 Tsunokamiawase body, (for example) the lid and tube. During mating, the stock solution flows in a closed internal space, preserving cells in a body fluid. The tube then may be subjected to processing to extract a plurality of cells in body fluids (e.g. saliva, urine) are set to receive a donor sample. The plurality of cells may be further processed to isolate one and / or another cell type from it. A plurality of cells and an isolated cell type (s), functional genomics and epigenetic research, and may be analyzed for biomarker discovery.