A case of pleomorphic adenoma of the lung with multiple distant metastases--observations on its oncogene and tumor suppressor gene expression.

Pleomorphic adenoma of the lung is a rare neoplasm. Here we describe the first report on oncogenes and tumor suppressor genes in metastasizing pleomorphic adenoma of the lung. A 48-year-old Japanese woman presented with metastasizing pleomorphic adenoma in which both the primary lung tumor and metastatic lesions were composed of benign pleomorphic structures. The mechanism of the metastatic potential was examined by analyzing known oncogenes and tumor suppressor genes by DNA blot analysis and immunohistochemistry. No rearrangements amplifications or overexpressions of oncogenes, bcl-2, c-erbB-2, c-myc, L-myc, N-myc, Ha-ras and Ki-ras were found. In addition, immunohistochemical studies showed no aberrance in expressions of the tumor suppressor gene products, RB, p16 and p53 in the tumor. Some unknown mechanism(s) seems to be responsible for the aggressiveness of this metastasizing pleomorphic adenoma. This mechanism must be elucidated by studies on further case of this rare tumor.