In the case of family history of cancer, although the OR for GSTM1 null genotypes was higher in study subjects, this was statistically nonsignificant (OR = 2.26, 95%Cl = 0.78–6.57, p = 0.155), which suggested that there was no lung cancer risk associated with the combination of GSTM1 null genotype and family history of cancer. Here, GSTM1 is linked to cancer.