Structural rearrangements of chromosome Nr 8 involving 8q12--a primary event in pleomorphic ademona of the parotid gland.

Nine pleomorphic adenomas of the human parotid gland were investigated. Within this series the group of cases having clonal aberrations of chromosome Nr 8 predominates. The occurrence of cases with trisomy-8 and cases with structural rearrangements involving a breakpoint in 8q11-8q13 allows a further subdivision of this group of tumors. Our special interest in this paper is devoted to the latter group. The hypothesis is proposed that in these cases the chromosomal rearrangement is the primary event in tumorigenesis, leading to activation of a so far unknown oncogene located most likely at 8q12. The translocations to different recipient chromosomes may serve as sign posts to transcriptionally active chromosomal domains in the salivary gland.