Molecular Analysis of Chromosome 16q Regions in Dermal Analogue Tumors of Salivary Glands: A Genetic Link to Dermal Cylindroma?

Dermal analogue tumor, an uncommon subtype of basal cell monomorphic adenoma of the parotid gland, has a remarkable clinical and histologic resemblance to dermal cylindroma. Molecular studies of familial and sporadic cylindromas have shown frequent alterations at chromosome 16q12–13 that have recently been found to house the cylindromatosis gene (CYLD). To determine the involvement of the chromosome 16q12–13 region in dermal analogue tumors, we performed loss of heterozygosity analysis using microsatellite markers flanking the cylindromatosis gene locus in 21 sporadic dermal analogue salivary tumors and 12 salivary and dermal lesions from two sisters. Loss of heterozygosity was identified in 17 (80.9%) of the 21 sporadic tumors and in nine of the 12 dermal and salivary gland dermal analogue tumors from the two sisters; a parathyroid adenoma from one sister and two lymphoepithelial lesions from the second sister showed no microsatellite alterations. Microsatellite instability was only identified in three sporadic tumors at marker D16S308. Markers D16S409 (centromeric), D16S541, and D16S308 (telomeric) to the CYLD gene showed the highest incidence of loss of heterozygosity (>65%). The minimally deleted region was flanked proximally by marker D16S389 and distally by marker D16S419 and spanned the 771.5-megabase fragment that included the CYLD locus. We conclude that dermal analogue tumor and cylindroma share similar incidence of alterations at the 16q12–13 region, supporting a common molecular origin.