Mutagen‐induced chromosome fragility within peripheral blood lymphocytes of head and neck cancer patients

The expression of chromosome breakage as a response to mu‐tagen exposure may contribute to the development of head and neck cancer. Lymphocytes from 46 previously untreated head and neck cancer patients were cultured in vitro and exposed to the radiomimetic clastogen, bleomycin. The lymphocytes were then arrested in metaphase and analyzed for bleomycin‐induced chromosome breaks. Mean bleomycin‐induced chromosome breaks per cell (b/c) in head and neck cancer patients (0.94 ± 0.3 b/c) were significantly higher than in either controls (0.70 ± 0.3 b/c; p < 0.001) or a concurrently examined patient population with central nervous system tumors (0.55 ± 0.3 b/c; p < 0.001). The expression of mutagen‐induced chromosome fragility in the head and neck cancer population was site‐specific, being most evident in patients with laryngeal or pharyngeal cancer but not oral cavity disease. The differential responses to muta‐gen effects may be a reflection of DNA repair deficiency. Head and neck cancer patients express a higher degree of chromosomal mutagen sensitivity, which may contribute to neoplastic development.