Genetic aberrations were examined to assess the possible roles that p53 and retinoblastoma susceptibility genes might have played in the development of small cell cervical carcinomas. Cervical cancer tissues from 12 patients with small cell cervical carcinoma that were free of human papillomavirus were analyzed. The presence of mutational alterations were examined by polymerase chain reaction-single-strand conformation polymorphism and by direct DNA sequencing. None of 12 small cell cervical carcinomas were found to contain mutations in regions of p53 and retinoblastoma susceptibility genes that were functionally important and where most mutations, in human tumors have been found. Furthermore, there was no evidence indicative of loss of heterozygosity of chromosome region 17p13 (in which p53 is located) in these tumors. These data seem to suggest that whereas mutant type of p53 and retinoblastoma susceptibility genes may exhibit "oncogenic" function in many human tumors, mutational inactivation of these genes may not be an important feature in the carcinogenic development of human papillomavirus-negative small cell cervical carcinomas.