Tehran University of Medical Sciences Basic & Clinical Cancer Research 2228-6527 7 4 2016 06 08 2 8 EN Farshid Farhan Radiotherapy Oncology Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran. Majid Mahmoodi Cancer Research Center, Tehran University of Medical Sciences, Tehran, Iran. Cyrus Azimi Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences. Tehran, Iran. Mohammad-Ali Mohagheghi Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences. Tehran, Iran. Farideh Farzanfar Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences. Tehran, Iran. Azam Noormohammadi Radiotherapy Oncology Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran. Malihea Khaleghian Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences. Tehran, Iran. Mahbod Esfahani Radiotherapy Oncology Research Center, Cancer Institute of Iran,Tehran University of Medical Sciences, Tehran, Iran. Abbas Jafari Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences. Tehran, Iran. Zahra Safari Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences. Tehran, Iran Kouros Divsalar Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences. Kerman, Iran. 2016 03 07 2016 05 29 Background: The aim of this study was to test the in vitro sensitivity of lymphocytes of patients with head and neck cancer against gamma irradiation and also to find out if the frequencies of chromosomal aberrations correlate with side effects of radiotherapy. Methods: Peripheral blood of 101 patients with head and neck cancer was collected before the onset of radiotherapy, cultured and irradiated in the G-2 or the G-0 phase of the cell cycle. Lymphocytes of 40 healthy donors were treated in the same way. Chromosomal aberrations such as chromosome and chromatid breakages, chromosome and chromatid gaps, chromatid exchanges and micronuclei were scored in metaphase cells of the patient and control groups. Results: The frequency of radiation- induced G2 aberrations in lymphocytes of patients were on average higher than that of healthy donors (P=0.001 for chromosomal breaks). The frequency of radiation-induced micronuclei in the G0 assay were also higher in patients than that in controls (P=0.05). The results also indicate that there is no correlation between the two assays. No significant correlation was observed between aberration frequencies in lymphocytes and the degree of both early and late normal tissue reactions. Conclusion: The induced chromosomal aberration frequencies in lymphocytes of patients with head and neck cancer are higher than those in healthy individuals, however, it does not appear to have a predictive value for the risk of developing side effects to radiotherapy https://bccr.tums.ac.ir/index.php/bccrj/article/view/184 https://bccr.tums.ac.ir/index.php/bccrj/article/download/184/02