Objective   To investigate the correlation between the single nucleotide polymorphism (SNP) of Matrix metalloproteinsase-9 (MMP-9) gene and esophageal squamous cell carcinoma patients in Southwest China.    Methods   The polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLPs) technique was applied to analyze the MMP-9 R279Q polymorphism in normal group (300) an

d ESCC group (235).     Results   Frequencies of the MMP-9 279R and 279Q allele distribution in ESCC patients and healthy control were 57.7%

42.3% and 51.5%

48.5%

respectively (χ

2

=4.08

P=0.04). The frequency of the R/R genotype in the MMP-9 gene polymorphism increased significantly in ESCC patients (40.5%) as compared with that in the controls (29.0%) (χ

2

=20.08

P=0.01). Age-stratified analysis showed R/R genotype significantly increased the risk of ESCC in individuals younger than 50 years (adjusted OR=3.39

95%CI=1.23~9.29).     Conclusion   The R allele of MMP-9 gene R279Q might be associated with the increased susceptibility to ESCC. The R homozygote might increase the risk of ESCC. Our results indicated that MMP-9 R279Q polymorphism might be associated with genetic susceptibility to ESCC in Southwest Chinese population.