RESUMO
The C677T and A1298C polymorphisms in methylene-tetrahydrofolate reductase (MTHFR), which regulates the release of active folate in the body, may have reduced activity. Given that folate participates in important intracellular pathways, such as nucleotide synthesis and biomolecule methylation, it seems plausible that patients with head and neck squamous cell carcinoma (HNSCC) may respond differently to radiotherapy treatments, based on genetic polymor-phisms. Therefore, this study sought to understand the role of these polymorphisms in HNSCC patient radiotherapy response. Genotypes were detected by PCR-RFLP after extraction of DNA from peripheral blood lymphocytes. Survival curves were analyzed by the Kaplan- Meier model, and significant differences were analyzed by the Wil-coxon test. Response to radiotherapy in patients with laryngeal SCC was significantly associated with the MTHFR C677T polymorphism (P = 0.030). Indeed, the presence of at least one T allele decreases the mortality rate up to 3-fold. Therefore, we propose that MTHFR C677T may represent a putative biomarker for radiotherapy prognosis in la-ryngeal SCC patients.
Assuntos
Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/radioterapia , Neoplasias de Cabeça e Pescoço/genética , Neoplasias de Cabeça e Pescoço/radioterapia , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Polimorfismo de Nucleotídeo Único , Adulto , Idoso , Alelos , Carcinoma de Células Escamosas/diagnóstico , Carcinoma de Células Escamosas/mortalidade , Feminino , Genótipo , Neoplasias de Cabeça e Pescoço/diagnóstico , Neoplasias de Cabeça e Pescoço/mortalidade , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Carcinoma de Células Escamosas de Cabeça e Pescoço , Resultado do TratamentoRESUMO
The aims of this study were to analyze the polymorphisms XRCC1 Arg194Trp, XRCC1 Arg399Gln, XRCC3 Thr241Met, XPC Lys939Gln, ERCC1 Asn118Asn, and RAD51 -98G>C and to verify their influence on radiotherapy response and prognosis of patients with head and neck squamous cell carcinoma (HNSCC). Peripheral blood DNA was extracted from 311 patients and analyzed by PCR-RFLP. Our results showed that in irradiated oral and oropharyngeal patients, the 939Gln allele increased 6-fold local disease relapse risk (OR = 6.04; CI = 1.47-24.88) and over 2-fold the earliness of relapse (HR = 2.63; CI = 1.04-6.70). As for the XRCC3 polymorphism, multivariate analysis showed that the 241Met allele increases over 33-fold local relapse risk (OR = 33.64; CI = 3.23-350.85), over 12-fold earliness of relapse (HR = 12.55; CI = 2.47-63.73) and over 3-fold earliness of death (HR = 3.04; CI = 1.08-8.61). For polymorphism RAD51 -98, multivariate analysis showed that allele C increases over 3-fold the risk of relapse (OR = 3.13; CI = 1.12-8.78) and over 2-fold the earliness of relapse (HR = 2.84; CI = 1.25-6.47). For polymorphism XRCC1 Arg399Gln, multivariate analysis showed that the 399Gln allele increased the risk of local disease relapse for irradiated oral and oropharyngeal patients (OR = 3.35; CI = 1.10-10.13) by over 3-fold. Based on these results, we suggest that these polymorphisms may be useful markers of prognosis in HNSCC.
