MMP9 and laryngeal neoplasm: A study by Zhu Li et al. investigated (SNP) polymorphisms for the genes XPG, CYP1A1, OGG1, ERCC5, ERCC1, MMP2 and MMP9 in a group of 200 patients with larynx cancer associated with heavy smoking in Shanghai (China), finding an association between SNP of genes CYP1A1 and MMP9 and larynx cancer.