Immunohistochemical study of fibronectin expression in cancer tissue before and after irradiation

: We examined the expression and distribution of fibronectin in cancer tissues from 19 patients with cancer of the head and neck regions. Samples taken before and after irradiation with approximately 10 Gy and 20 Gy or 30 Gy were immunohistochemically stained by the avidin-biotin-horseradish peroxidase method using a monoclonal antibody against human fibronectin. No remarkable changes in the expression or distribution pattern of fibronectin were found between tissue specimens taken before and after each dose of irradiation. The prognosis, however, differed according to the pattern of fibronectin distribution. Eight patients in whom the cancer tissue was thickly encircled by fibronectin are alive without local recurrence or distant metastasis. Meanwhile, six patients in whom fibronectin was expressed faintly or focally (or scattered) in the cancer tissue died or developed recurrence soon after treatment. These findings indicate that the immunohistochemical analysis of fibronectin in cancer tissue exposed to irradiation may be applicable as a predictive assay in radiotherapy of cancer.