Molecular analyses of the candidate tumor suppressor gene, PLAGL1, in benign and malignant salivary gland tumors.

Deletions affecting the long arm of chromosome 6 are a characteristic feature of all major subtypes of malignant salivary gland tumors. Moreover, a subgroup of adenoid cystic carcinomas have t(6;9)(q23-25;p21-24) translocations with breakpoints located within the commonly deleted region. Here we have examined the possible involvement of the candidate tumor suppressor gene, PLAGL1, in these deletions and translocations. Northern blot and fluorescence in situ hybridization (FISH) analyses of a series of 27 salivary gland tumors revealed no significant changes in the gene expression or rearrangements of PLAGL1. FISH analysis also demonstrated that the 6q translocation breakpoint in adenoid cystic carcinomas with t(6;9) is proximal to the PLAGL1 locus. Collectively, these results indicate that PLAGL1 is not likely to be the major target gene of the 6q rearrangements in salivary gland tumors.