[Adult nasopharyngeal mucosa xenograft and dinitrosopiperazine carcinogenesis in nude mice].

Adult nasopharyngeal mucosa from 44 patients of chronic nasopharyngitis diagnosed by pathology were transplanted into 59 nude mice. The control group, 13 nude mice, were given no treatment. 10 16 days after transplantation, the experimental group, 46 nude mice, were subcutaneously injected dinitrosopiperazine (DNP), 15mg/kg, twice a week, for 12-30 times. In the experimental group, the xenografts in 27 nude mice were examined 18-37 weeks after transplantation, and the epithelia survived in 20 mice. The survival rate was 74.1%. The survival epithelia showed focal hyperplasia, dysplasia (7/20) and carcinomatous changes (4 carcinoma in situ and 4 early infiltrating carcinoma). The carcinoma incidence was 40%. In the control group, the xenografts in 7 nude mice were examined 8-35 weeks after transplantation, and the epithelia survived in 6 mice. The survival epithelia did not develop dysplasia or carcinomatous changes. The results suggested that DNP may induce precarcinomatous lesions and carcinomatous changes of adult nasopharyngeal epithelia in nude mice. On the basis of these results, the factors related to the carcinomatous changes of the nasopharyngeal epithelia are analyzed and discussed.