The checkpointkinase 2 (CHK2) 1100delC germ line mutation is not associated with the development of squamous cell carcinoma of the head and neck (SCCHN)

We investigated 91 patients suffering from SCCHN including all tumor sites (oropharynx, hypopharynx, larynx) for the presence of the germ line mutation 1100delC by direct sequence analysis. Patients were characterized by their tumor localization, tumor stage, age, the presence of additional malignant tumors and predisposing carcinogens (smoking, alcohol abuse).None of the patients, independently of the tumor site, age, the abuse of predisposing carcinogens, or the presence of other kinds of tumors, carried the CHK2 1100delC variant.The germ line CHK2 1100delC variant does not seem to have a major impact on the development of SCCHN.Head and neck cancer is the fifth most common cancer in the world [1]. The tumor suppressor p53 is strongly involved in the carcinogenesis of these tumors and inactivated either by mutations or human papilloma virus (HPV) infection in most of the cases [2]. Furthermore, squamous cell carcinomas of the head and neck (SCCHN) are associated with smoking and alcohol consumption as risk factors for their development [3]. These genotoxic substances lead to DNA damage; in particular DNA double strand breaks that are removed by different DNA repair mechanisms in healthy cells [4]. Two main checkpoint pathways are initiated in response to DNA damage and lead to either apoptosis or cell cycle arrest to allow chromatin repair: the ATR (ataxia telangiectasia and Rad3 related)-CHK1 (checkpoint kinase 1) -pathway and the ATM-CHK2-pathway. The checkpoint kinase 2 (CHK2, CHEK2) acts as a signal transducer within the highly conserved ataxia telangiectasia-mutated (ATM) protein kinase - CHK2-signaling pathway.[5-10] Germ line mutations of p53 are normally the hallmark of patients with Li-Fraumeni syndrome, who typically develop tumors at an early age of life at different sites. In 1999, Bell et al. described CHK2 germ line mutations in patients suffering from Li-Fraumeni syndrome or Li-Fraumeni-like syndrome [11] without a germ line p53 mutation. One of the