ALLELOTYPE OF SALIVARY-GLAND TUMORS

To elucidate the genetic alterations that occur in salivary gland tumo rs, we screened every autosomal arm (and the X-chromosome) of 29 prima ry human salivary gland neoplasms (11 pleomorphic adenomas, 10 adenoid cystic carcinomas, 5 mucoepidermoid carcinomas, and 3 carcinoma ex-mi xed tumors) for allelic loss using 86 microsatellite markers. A minimu m of two microsatellite markers were used per chromosomal arm to achie ve informativity of at least 60% (excluding X). The pleomorphic adenom as demonstrated few areas of allelic loss; the most prominent chromoso mal arm involved was 12q, lost in more than 35% of informative cases. The most significant allelic losses in adenoid cystic carcinoma were 1 p, 2p, 6q, 17p, and 20p (> 20% of informative cases) and 19q (40% of i nformative eases), Mucoepidermoid carcinoma showed 50% or greater Loss at 2q, 5p, 12p, and 16q. Although losses at 9p, 3p, and 17p are commo n in squamous cell carcinoma of the head and neck, only the carcinoma ex-mixed tumors demonstrated loss at these loci, consistent with progr ession to a more aggressive phenotype. Salivary gland tumors display a llelic loss patterns different from many other tumor types, suggesting distinct genetic pathways in the progression of these tumors.