{'fraction_non_alphanumeric': 0.024062278839348902, 'fraction_numerical': 0.016985138004246284, 'mean_word_length': 5.042735042735043, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
[Influence of genetic variation in the major histocompatibility complex on head and neck cancer susceptibility].

BACKGROUND
While cigarette smoking and alcohol consumption are risk factors for squamous cell carcinomas (SCC) of the head and neck, genetic factors are also significant. The gene of tumor necrosis factor (TNF) is located in the major histocompatibility complex class III and the cytokine has pleiotropic actions some of which are anticarcinogenic. As this gene complex is polymorphic with microsatellite markers identified it is a further candidate for head and neck cancer susceptibility.


METHODS
We used a case-control approach to study the influence of polymorphism at the A-D markers on susceptibility in 113 controls, 265 laryngeal and 123 oral cavity/pharyngeal SCC cases. Genotypes were identified on polyacrylamide gels in an automated DNA sequencer after amplification with fluorescently-labeled primers.


RESULTS
We found no differences in allele frequencies between controls and oral cavity/pharyngeal SCC cases but the frequency of B3 was greater in the laryngeal SCC cases than controls (p = 0.004, odds ratio 2.8). Homozygosity for B3 conferred an increased risk of laryngeal cancer compared with controls (p = 0.021, odds ratio 10.8).


CONCLUSIONS
The data provide the first evidence that allelism at MHC class III microsatellite markers is associated with risk to laryngeal SCC.