多形性腺瘤（ PA）是唾液腺最常见的上皮性肿瘤，具有交界性肿瘤的特性，肿瘤病程长或多次复发可恶变为恶性PA。 PA的恶变过程是多基因、多因素参与的。细胞染色体改变、基因变异、表观遗传学改变以及转录因子、细胞周期调控因子、细胞黏附分子等各种调控因子的改变均参与唾液腺PA的恶变过程。“,”Pleomorphic adenoma(PA) is the most common salivary epithelial tumor,with the character-istics of borderline tumor,and those with long disease course or multiple recurrence may develop into malig-nant PA.Multiple factors and genes are involved in the malignant transformation.Chromosome alternations, gene mutation,epigenetic changes and changes of several kinds of regulatory factors,such as transcription fac-tors,cell cycle regulators,cell adhesion molecules,all play important roles in the process.