[Hidden chromosome instability and risk of laryngeal cancer incidence]

The bleomycin test is a recognised method of evaluation of hidden genetical instability. The concept of the test consists in inducing chromosome aberrations in lymphocytes exposed in vitro to bleomycin and subsequent quantitative analysis of chromosome breaks. The study material was whole venous blood from 61 laryngeal cancer patients and from 30 healthy persons taken as a control. For each patient two parallel cultures where carried out in the standard procedure. Bleomycin was added to one of the cultures to induce chromosome breaks. Then, in microscopic metaphasal plates stained by Giemsa dye, the chromosome instability index estimated as a number of chromosome breaks per cell (b/c) and the percentage of cells with chromosome breaks were calculated. Higher indices of chromosome instability were demonstrated in laryngeal cancer patients in comparison to the controls. The persons with chromosome instability (b/c > 0.8) or with chromosome oversensitivity to mutagens (b/c > 1) were identified only among larynx cancer subjects. Furthermore, it was established that an increased chromosome instability is associated with high aggressiveness recognised by histological grading. The latter finding requires confirmation on an enlarged group of subjects.