Relationship between radiosensitivity of nasopharyngeal carcinoma and MDR1 gene polymorphism

Objective To investigate the relationship between human multidrug resistancel gene (MDR1) polymorphisms and the radiosensitivity of nasopharyngeal carcinoma (NPC). Methods Blood samples were collected from 59 NPC patients, who were devided into radiosensitive or radioresistant groups according to their responses to radiation therapy. The genotypes for MDR1 polymorphisms (G2677T in exon 21 and C3435T in exon 26) and their haplotypes were determined by PCR and restriction fragment length polymorphism analysis. The results were further confirmed by sequencing. Results The 3435CC genotype was associated with a significantly better response to radiotherapy than combined 3435 CT and TT genotype (P=0.026). The 2677GG genotype was also associated with a better response in comparison with combined 2677 GT and TT genotype, but this relation was not statistically significant. Patients with 2677G-3435C haplotype had a significant better response to radiotherapy than those with the other haplotypes (P=0.017). Conclusion The MDR1 G2677T and C3435T polymorphisms may help predict the response to radiotherapy in NPC patients.