Malignant transformation of human fetal lung fibroblasts induced by nitrosamine compounds in vitro.

This report, for the first time, demonstrates that diethyl-nitrosamine (NDEA) and a new nitrosamine compound-N-1-methylacetonyl-N-3-methylbutyl-nitrosamine (MAMBNA), which are suspicious carcinogens of esophageal cancer (EC) in Linxian, Henan Province, are able to cause the malignant transformation (altered morphology, extended life span, anchorage independent growth, invasiveness, tumorigenicity, etc.) of normal diploid fibroblasts derived from human fetal lung. Besides, the preselection for clonogenic cells, which seem to be more readily to be transformed, in soft agar before carcinogen treatment, could be considered as one of the useful ways in establishment of a model system of malignant transformation of human fibroblasts in vitro.