A new cell line, CUMC-6, has been derived from an invasive nonkeratinizing squamous cell carcinoma of the uterine cervix in a 31-year-old patient. It has been maintained in long-term culture for 61 months, and passaged over 300 times. Monolayer-cultured cells were polygonal in shape, showing a pavement-like arrangement and a tendency to pile up without contact inhibition. The epithelial nature of the cultured CUMC-6 cells was confirmed by transmission electron microscopy which demonstrated the presence of desmosomes and tonofilaments. The subcutaneous injection of cultured cells into nude mice gave rise to fast-growing tumors. The transplanted tumor showed similar histological features, but poor differentiation compared to the original tumor. Cultured CUMC-6 cells produced human chorionic gonadotropin beta-subunit (beta-HCG) and alpha-fetoprotein (AFP). Cytosol estrogen and progesterone receptors were not measured in this cell line. The results of isozyme analyses were distinct from the HeLa cell line. Repeated chromosome analysis from passage 6 to 300 revealed that most metaphases of this cell line contained diploid number of chromosomes. The structural abnormality consistently observed in this cell line was the elongation of short arm of chromosome 1. The G- or R-banded pattern of this chromosome suggested inv dup (1) (1pter-->1p34[symbol: see text] 1p21-->1p34[symbol: see text] 1p34-->1qter). Human leukocyte antigen (HLA) typing of CUMC-6 cells indicated the presence of DR12 and DQw3. Analysis of the DNA extracted from the CUMC-6 cells showed the presence of human papillomavirus (HPV) type 16 and 18 DNAs. The results of oncogene analyses using Southern blotting technique revealed amplification and rearrangement of oncogene c-myc and no amplification of oncogene L-myc. Using the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) technique, we have screened CUMC-6 cells for p53 mutation in exons 4 to 9. No mobility shift was observed in this cell line. These results suggest that chromosome 1 abnormality, oncogene alteration, and HPV infection work together in cervical tumorigenesis.