Pleomorphic adenoma（PA） is the most common salivary gland neoplasm. The tumor could transform to malignancy as malignant pleomorphic adenoma（MPA）, if the preexisting PA remains for long time or after multiple recurrences. During the malignant transformation, multifactors and multigene alterations are involved. The recent studies demonstrate that cytogenetic alterations, oncogenes, tumor suppressor genes, adhesion molecules and extracellular matrix proteins may play important roles in the process. This article summarized some advances in the mechanisms of the malignant transformation of salivary pleomorphic adenoma.
