APEX1 and glioblastoma: Genetic epidemiologic studies have showed that the APE1/Ref-1 Glu allele alone was associated with an increased risk of breast caner [16] and gastric cancer [17], and with a decreased risk of cutaneous melanoma [18] and gliomas [19], whereas no associations were found in prostate cancer [20], pancreatic cancer [21] and glioblastoma [22].