Proliferative activity of intratumoral fibroblasts in lung cancer and its implications

Abstract

The interaction between tumor cells and stroma cells plays an important role in the invasion and metastasis of tumor. The purpose of this study is to evaluate the proliferative activity of fibroblasts in lung cancer, and to explore its correlation with tumor biologic behavior. Ninety-four cases of surgically resected specimens of lung cancer were collected. The proliferative activity of fibroblasts was immunohistochemically evaluated with the mouse monoclonal antibody against proliferating cell nuclear antigen (PCNA). The tumor cells in the outer area had significantly higher PCNA label index (LI) than those in the inner area, however, the PCNA LI of fibroblasts in the inner area was significantly higher than those in the outer area regardless of tumor size. The PCNA LI of fibroblasts in the paracancerous tissues was significantly lower than that of fibroblasts in the inner or outer area of tumor. There was a significant correlation between the PCNA LI of fibroblasts and that of tumor cells in the inner or outer area of tumor. The PCNA LI of fibroblasts in either inner or outer area showed a significant correlation with lymph node metastasis of lung cancer. The results demonstrate that there is a discrepancy in the distribution of highly proliferative tumor cells and highly proliferative fibroblasts in lung cancer. The proliferative activity of tumor cells should be assessed in tumor cells in the outer area, and proliferative activity of fibroblasts should be assessed in fibroblasts in the inner area.