Genetic changes in sporadic keratocystic odontogenic tumors (odontogenic keratocysts).

Little is known about the genetic background of keratocystic odontogenic tumors (KCOT, odontogenic keratocysts). Our aim was to characterize genomic aberrations in sporadic KCOT using cDNA-expression arrays and array-comparative genomic hybridization. For cDNA-expression arrays, 10 KCOT specimens and 20 fetal tooth germs were studied. Quantitative real-time reverse-transcription/polymerase chain-reaction and immunohistochemical studies were also undertaken. Several genes were over-expressed in 12q13, including cytokeratin 6B (KRT6B) ( approximately 10-fold), epidermal growth factor receptor ERBB3 (approximately 4.7-fold), and glioma-associated oncogene homologue 1 (GLI1) (approximately 5- to 12-fold). One amplicon (approximately 0.7 Mega base pairs [Mbp]), covering several genes involved in the regulation of cell growth, was found in 12q13.2. Deletions were found in 3q13.1, 5p14.3, and 7q31.3, including the cell-adhesion-related gene cadherin 18 (CDH18) and leukocyte cell adhesion molecule (ALCAM, MEMD). Over-expressed and amplified genes in 12q13, also reported in several other tumors and cell lines, may contribute to the persistent growth characteristics of KCOT.