Mucoepidermoid tumor of the parotid gland showing a translocation (3;8)(p21;q12) and a deletion (5)(q22) as sole chromosome abnormalities.

The cytogenetic findings in a mucoepidermoid tumor of the parotid gland are described. In addition to a t(3;8)(p21;q12), all cells analyzed showed a deletion of part of the long arm of chromosome 5. Although the typical translocation of benign pleomorphic adenomas was found, histologic examination did not show remnants of a pleomorphic adenoma. Nevertheless, we assumed that the malignant tumor most likely arose in a preexisting pleomorphic adenoma. As a mechanism for malignant transformation, the loss of a suppressor gene located on the long arm of chromosome 5 is discussed.