To determine the role of the p53 gene in the pathogenesis of basal cell carcinoma (BCC), we screened mutations of the gene in 11 cases of BCCs using the polymerase chain reaction (PCR) and single-stranded conformation polymorphism (SSCP). However, in all the coding exons of the gene analysed, no evidence suggesting the mutations were obtained. On the other hand, in 2 of 5 informative cases of our BCCs (40%) we found loss of heterozygosity (LOH) for loci on chromosome 9q31 which is linked to the Gorlin syndrome, that predisposes to BCC. Therefore, we suggest that a putative tumor suppressor gene on the region of 9q, but not p53 gene, plays a critical role in the pathogenesis of BCC, independent of race.