Human papilloma virus (
HPV) infection is a major cause of
cervix cancer, but a number of infected women do not develop invasive lesions, suggesting that
HPV infection in itself is not a sufficient factor and that other cofactors, such as smoking, play an important role in development of
cervix cancer. Alongside active cigarette smoking,
passive smoking is an independent risk factor for
cervix cancer. Smoking maintains cervical
HPV infection longer and decreases potential of clearing an oncogenic
infection. Thus, it is quite possible that polymorphism at detoxifying
enzyme coding loci such as GSTM1, GSTT1, and GSTP1 may determine susceptibility to
cervix cancer. This study evaluates the combined effects of genetic polymorphisms of GSTM1, GSTT1, and GSTP1 on susceptibility to
cervical cancer and interaction of these genes with smoking. On individual analysis of GSTM1, GSTT1, and GSTP1, it was observed that passive smokers having genotypes GSTM1 (null) (OR = 7.0, 95% CI = 2.19-22.36, P = 0.0005), GSTT1 (null) (OR = 10.2, 95% CI = 1.23-84.18, P = 0.02), and GSTP1 (
ile/val) (OR = 6.4, 95% CI = 2.25-18.38, P = 0.0005) have an increased risk of developing
cervix cancer. It is thus concluded that
cervical cancer risk is increased in passive smokers with GSTM1 (null), GSTT1 (null), and GSTP1 (
ile/val) genotypes.