Identity of non-malignant human urothelial cell lines classified as transformation grade I (TGrI) and II (TGrII).

Restriction fragment length polymorphism (RFLP) and marker chromosome or isozyme analysis were used to study the identity of 7 human urothelial cell lines selected according to their HLA-A,B phenotype. The results confirmed that the cell lines Hu961b, Hu1125, Hu1694, Hu1752, Hu609 and HCV-29 were genuine cell lines of different origin, while Hu1734 and HCV-29 were of the same origin. Hu609 was recorded to be derived from a female. However, the presence of a Y chromosome indicated either false labelling or cross-contamination. Analysis of a series of frozen stocks of Hu609 cultures showed that "malignant transformation" of these cultures was due to cross-contamination.