An epidermoid carcinoma cell line derived from hamster 7,12-dimethylbenz[a]anthracene-induced buccal pouch tumors

w cell line, HCPC I, was established from an epidermoid carcinoma of the Syrian golden hamster cheek pouch. The carcinoma was induced by applications three times a week of a 0.5% solution of 7,12-dimethylbenz[a]anthracene (DMBA) in heavy mineral oil. The HCPC I cell line has been maintained through 60 passages over 15 months. Electron microscopy of the cell line revealed tonofilaments and desmosomes, thereby confirming its epithelial nature. Presence of keratin in the HCPC I cells was demonstrated by both histochemical and indirect immunofluorescence studies. The population-doubling time of HCPC I, estimated from the exponential growth phase of the growth curve established for the cell line, was 12 hours. The plating efficiency of the cell line was estimated at 35%. When an inoculum size of HCPC I, numbering 2.4 X 10(7) cells, was transplanted to the cheek pouch of an immunosuppressed inbred hamster, a papillary tumor, measuring 5 X 1 mm and microscopically diagnosed as a well-differentiated epidermoid carcinoma, developed 1 week post transplantation. Further successful transplantation was achieved with 1.8 X 10(7) HCPC I cells inoculated into the cheek pouch of a nonimmunosuppressed inbred hamster. A raised plaquelike mass, microscopically diagnosed as invasive epidermoid carcinoma, developed in the hamster cheek pouch 5 weeks post transplantation. Furthermore, 5 nonimmunosuppressed hamsters that received 1 X 10(6) HCPC I cells on their cheek pouches developed tumors microscopically diagnosed as anaplastic carcinomas 14 weeks post transplantation. The largest of these tumors measured 2 cm in diameter.