The Hep-2 cell line has been described to originate from tumours which were produced in irradiated-cortisonised weanling rats after injection of epidermoid carcinoma tissue isolated from the larynx of a 56 year old male. STR (DNA)-profiling has revealed that the Hep-2 cell line is almost identical to the HeLa cell line. The cells are positive for keratin by immunoperoxidase staining.