An overlapped record means a match between VIS and 1 of 3 Cistrome factor (histone modification, transcription factor binding site and chromatin accessibility), more specifically, this match includes at least 1 overlap between this VIS and 1 Cistrome factor-related sample from 1 of 3 Cistrome factor data. So one VIS may have several overlaps with multiple Cistrome factor-related samples, the associated factor and overlap amount of samples could indicate that the virus integration site is a potentially functional DNA element.