CD34-positive stromal cells in primary lung carcinomas.

To investigate the phenotypes of stromal cells in primary lung carcinomas, we examined the distribution of CD34-positive stromal cells in primary lung carcinomas, with special reference to histological types. In total 26 surgically resected primary lung carcinomas (13 adenocarcinomas, 10 squamous cell carcinomas, 2 large cell carcinomas, and 1 small cell carcinoma and their normal tissues were examined. CD34-positive stromal cells were observed in connective tissue adjacent to the bronchiolar and bronchial epithelium in normal lung tissues. Nine of the 13 adenocarcinomas had CD34-positive stromal cells in the tumor stroma, whereas none of the other histological type tumors examined had CD34-positive stromal cells. These results suggest that CD34-positive stromal cells are specific in the stroma of primary lung adenocarcinomas, and there is a possibility that CD34-positive stromal cells may play a supportive role in primary lung adenocarcinomas.