Objective     To establish a malignant transformed human fetal osteoblastic human cells from the immortalized cell line hFOB1.19 in order to explore the molecular mechanism in tumorigenesis of osteosarcoma.      Methods     hFOB1.19 cells were treated sequentially by an initiated factor

N-methyl-N’-nitro-N-nitrosoguanidine (MNNG) and a promoter

12-O-tetradecanoyl phorbol-13-acetate (TPA). The features of malignancy of transformed cells were identified by cell morphology

DNA content analysis

colony forming frequency on soft agar and tumorigenetic test in nude mice.      Results     Continuous passaging after the treatments resulted in the formation of a few paramorph foci and exhibited in an extensively random orientation. The poly-ploid of DNA was 81.08% in experiment group

much higher than that in control group (55.03%). Compared with that of negative control cell

colony formation efficiency of transformed cells in semisolid agar showed a a significant increase. The transformed cells formed tumors subcutaneously in the nude mice

which were verified to be poorly differentiated osteosarcoma histopathological examination.      Conclusion     Mocking the process of malignant transformation of human cells

we establish malignant transformed immortalized human fetal osteoblastic human  cells (hFOB1.19) model.