DNA-DAMAGE PROCESSING IN BLOOD-LYMPHOCYTES OF HEAD-AND-NECK-SQUAMOUS-CELL-CARCINOMA PATIENTS IS DEPENDENT ON TUMOR SITE

It has been reported that an intrinsic susceptibility to cancer is rel ated to the way an individual responds to DNA-damaging agents. The aim of this study was to evaluate whether, in addition to bleomycin-induc ed chromosomal instability, radiation-induced initial DNA damage and s ubsequent repair is associated with the development of head-and-neck s quamous-cell carcinoma. In this study, 2 assays were performed to meas ure DNA damage in human peripheral-blood lymphocytes. One was a chromo somal aberration assay which determines sensitivity to chromatid break s induced by bleomycin, the other an elegant immunochemical assay whic h measures the level of radiation-induced strand breaks as well as sub sequent repair. Age, smoking and alcohol-drinking behavior did not inf luence the number of chromatid breaks, initial DNA damage or repair ca pacity. As has been found in previous studies, the mean number of chro matid breaks per cell was significantly different between patients (n = 18) and control persons (n = 19), whereas the amount of initial DNA damage was not, No correlation was found between the outcome of the 2 assays in the subject groups. In contrast to laryngeal-carcinoma patie nts, oral-cavity-carcinoma patients showed significantly slower repair capacity than controls. Our hypothesis is that the way DNA damage is processed by the patients determines at which site cancer develops in the head and neck area. (C) 1996 Wiley-Liss, Inc.