A number of environmental factors, such as tobacco and alcohol, have been 
implicated, through oxidative DNA damage, in the development of squamous cell 
carcinomas of the head and neck (SCCHN). Several pathways are involved in the 
repair of DNA lesions caused by oxidative stress, such as the base excision 
repair system (BER), which repairs mutation involving 8-oxoguanine and comprises 
the MUTYH, OGG1 and MTH1 genes. We analysed 29 patients, assessing germline 
polymorphisms or mutations in these genes by complete genomic sequencing of 
exons and adjacent intronic regions. Thirty healthy blood donors served as 
controls. No pathogenic germline mutations were identified. We found common and 
rare new variants in the coding and adjacent intronic regions. In summary, our 
data do not support a major role for MUTYH, OGG1 and MTH1 variants in the 
etiology of sporadic squamous oral/oropharyngeal carcinomas. This does not 
exclude the involvement of the three BER genes in the tumorigenesis of SCCHN 
through other mechanisms such as promotor hypermethylation, genomic 
rearrangements or mutations involving regulatory sequences.