Growth requirements and growth pattern of human urothelial cell lines of different grades of transformation.

Human urothelial cell lines propagated in culture have been classified into three grades of transformation (TGr I-III). This classification is unrelated to the histological classification of the original biopsy material. Mortal TGr I cell lines differed from immortal and nontumorigenic TGr II cell lines and tumorigenic TGr III cell lines; they have a lower growth rate, growth fraction, and saturation density, and a higher requirement for Ca2+. Except for one TGr II cell line, TGr II cells differed from TGr III cells by having a higher serum requirement and a lower saturation density. The ability to grow in agar was not correlated with the TGr of the cell lines.