FLO-1 was established from a primary distal oesophageal adenocarcinoma in a 68 year-old Caucasian male in 1991. The Y chromosome could not be detected in this cell line by short tandem repeat (STR)-PCR analysis. It is a known phenomenon that due to the increased genetic instability of cancer cell lines the Y chromosome can be rearranged or lost resulting in lack of detection.