[CANCER RESEARCH 62, 2819 –2823, May 15, 2002] Combinations of the Variant Genotypes of GSTP1, GSTM1, and p53 Are Associated with an Increased Lung Cancer Risk 1 David P. Miller, Geoffrey Liu, Immaculata De Vivo, Thomas J. Lynch, John C. Wain, Li Su, and David C. Christiani 2 Department of Environmental Heath, Occupational Health Program [D. P. M., G. L., L. S., D. C. C.] and Department of Epidemiology and Channing Laboratories, Harvard Medical School [I. D. V.], Harvard School of Public Health, Boston Massachusetts 02115, and Hematology Oncology Unit [G. L., T. J. L.], Thoracic Surgery Unit, Department of Surgery [J. C. W.], and Pulmonary and Critical Care Unit [D. C. C.], Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston Massachusetts 02114 ABSTRACT GSTP1 and GSTM1 are genes involved in Phase II metabolism, whereas p53 is a tumor suppressor gene. Individually, functional polymorphisms of these genes have been studied as risk factors for lung cancer. Small sample sizes have hindered the detection of possible increases in risk associated with having two or more “at risk” polymorphisms of these three genes. In a large Caucasian population, we examined the association of combined variant genotypes [or double-variants (DVs)] of these three genes and lung cancer risk, compared with their corresponding “double-wild-type” gen- otypes. Because these DVs may promote lung carcinogenesis at an earlier age, a subgroup of individuals aged 55 years or younger was examined separately. Using a case-control design, individuals were genotyped for GSTM1, GSTP1, and p53 codon 72 using PCR-RFLP techniques. All of the analyses used multiple logistic regression. Indicator variables were created to evaluate the risk for individuals with the following DVs: GSTP1 GG  GSTM1-null and GSTP1 GG  p53 Arg/Pro or Pro/Pro. A total of 1694 cases and controls were evaluated. In the whole popu- lation, those with the double variants have a higher risk of lung cancer when compared with those with the double-wild-type genotypes, support- ing our original hypothesis. Individuals with the GSTP1 and GSTM1, DV (P1-M1 DV) had a marginally significant higher risk of lung cancer compared with their double-wild-type counterparts [adjusted odds ratio (AOR), 1.60; 95% confidence interval (CI), 0.95–2.70]. A significantly higher risk was found for the GSTP1, p53 DV (P1-p53 DV; AOR, 1.99; 95% CI, 1.12–3.53). Among individuals aged 55 or younger, these risks were even higher: for the P1-M1 DV the AOR was 4.03 (95% CI, 1.47– 11.1); for the P1-p53 DV the AOR was 5.10 (95% CI, 1.42–18.30). Specific DVs of GSTM1, GSTP1, and p53 codon 72 are associated with a higher lung cancer risk. This susceptibility is highest among younger individuals. INTRODUCTION Genetic susceptibility is one of the primary hypotheses used to explain why a minority of smokers develops lung cancer. Genetic polymorphisms involved in metabolism of carcinogens have been studied as possible risk factors for lung cancer (1–10). GSTs, 3 a major group of enzymes whose main classes are , , , and , are directly involved in the detoxification step of this metabolic process (Phase II; Ref. 11). The expression of these enzymes differs among organs. GST  has the highest expression in the lung and is one of the main detoxifiers of the activated form of benzopyrene (12–14). GST  is encoded by a polymorphic gene, GSTP1. Polymorphisms of GSTP1 are a consequence of a single bp substitution, where (A) adenine is replaced by (G) guanine, leading to an amino acid substitution in which Isoleucine (I 105 ) is replaced by Valine (V 105 ). This substitution results in a lower enzymatic activity (15, 16) and is associated with higher hydrophobic adduct levels in lung tissue (7) and higher levels of polycyclic aromatic hydrocarbon-DNA adducts in human lympho- cytes (17). Recent studies examining the association between GSTP1 polymorphisms and lung cancer have found no statistically significant associations (2, 3, 8, 10, 18, 19). The polymorphism in the GSTM1 gene (which encodes for the GST  enzyme) is a germ line deletion (known as GSTM1-null), which results in a total loss of enzymatic function. The GSTM1-null genotype has been studied extensively with contradictory results as to whether there is any association with lung cancer risk (2, 4, 5, 7–9, 20 –23). More recently, polymorphic genes involved in cell cycle regulation, apoptosis, and tumor suppression have been studied as possible risk factors for lung cancer (9, 24 –26). p53 is one of these genes. Somatic point mutations in this gene have been associated with increased risk in various cancers. The gene is located on chromosome 17p13 and is one of the most commonly mutated genes in all of the human cancers (27, 28). The codon 72 p53 polymorphism is a result of a single bp substitution: guanine is replaced by cytosine leading to an arginine (Arg) replaced by proline (Pro). The wild-type p53 gene operates by suppressing cellular transformation by activated oncogenes, thus in- hibiting the growth of malignant cells (29, 30). Point mutations in p53 alter the DNA binding properties and transcription factor function, resulting in cellular proliferation (31). Several studies have reported that p53 Pro/Pro is associated with a higher risk of lung cancer (9, 24 –26). Mutations in the p53 gene have also been associated with altered repair and enhanced cytotoxicity because of DNA damage by benzo(a)pyrene diol epoxide adducts (32, 33). Individuals carrying more than one of the at risk polymorphisms may have a greater risk of developing lung cancer. Two studies found that the combination of GSTP1 GG and GSTM1-null genotypes was associated with a higher risk of lung cancer (2, 3). Another study found that lung cancer risk associated with the GSTM1-null polymor- phism increased in the presence of the p53 Pro allele (9). We con- firmed recently this association in our study population (34). Small sample size was a limiting factor in the previous studies. We reported recently a significant association between GSTP1 GG and early age onset lung cancer (diagnosed at 55 years or younger). 4 The presence of DVs may be associated with early age onset lung carcinoma through an accelerated accumulation of DNA damage leading to carcinogenesis. In this study, we tested the following a priori hypotheses on a large sample of 1694 participants (767 cases and 927 controls): (a) the GSTP1 GG, GSTM1-null DV combination (P1-M1 DV) is associated with increased lung cancer risk; (b) the GSTP1 GG, p53 variant (Pro/Pro + Arg/Pro) DV combination (P1-p53 DV) is associated with Received 1/21/02; accepted 3/20/02. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. 1 Supported by NIH Grants CA 74386, ES/CA 06409, and ES00002. 2 To whom requests for reprints should be addressed, at Occupational Health Program, Harvard School of Public Health, 665 Huntington Avenue, Building 1 Room 1407, Boston, MA 02115. Phone: (617) 432-3323; Fax: (617) 432-3441; E-mail: dchris@hohp.harvard.edu. 3 The abbreviations used are: GST, glutathione S-transferase; DV, double-variant; MGH, Massachusetts General Hospital; AOR, adjusted odds ratio. 4 D. P. Miller, J. C. Wain, D. Neuberg, and D. C. Christiani. An association between GSTP1 polymorphism and early age onset lung carcinoma in women, submitted for publication. 2819 Research. on December 8, 2021. © 2002 American Association for Cancer cancerres.aacrjournals.org Downloaded from