OncoTargets and Therapy Dovepress open access to scientific and medical research Open Access Full Text Article ORIGINAL RESEARCH Contribution of programmed cell death 6 genetic variations, gender, and smoking status to lung cancer This article was published in the following Dove Press journal: OncoTargets and Therapy – Te-Chun Shen1 3,* Purpose: Programmed cell death 6 (PDCD6) is a calcium sensor participating in T-cell Wen-Shin Chang1,2,* receptor-, Fas-, and glucocorticoid-induced programmed cell death. At the sites of lung Te-Chun Hsia1,3,4,* tumors, the expression of PDCD6 is higher than that in non-tumor tissues. However, the Hsin-Ting Li1 contribution of variant PDCD6 genotypes to lung cancer is largely unknown. The current Wei-Chun Chen3,4 study aimed to evaluate the contributions of the PDCD6 rs4957014 and rs3756712 genotypes to the risk of lung cancer. Chia-Wen Tsai1,* Patients and methods: The contributions of PDCD6 genotypes to lung cancer risk were Da-Tian Bau1,2,5,* examined among 358 patients with lung cancer and 716 age- and gender-matched healthy 1Terry Fox Cancer Research Laboratory, controls by typical polymerase chain reaction-restriction fragment length polymorphism Translational Medicine Research Center, (PCR-RFLP) methodology. China Medical University Hospital, Taichung, Taiwan; 2Graduate Institute of Results: The results showed that the GG but not the GT genotype of PDCD6 rs4957014 was Clinical Medical Science, China Medical associated with a decreased risk of lung cancer (odds ratio (OR) =0.41, 95% confidence University, Taichung, Taiwan; – 3Department of Internal Medicine, China interval (CI) =0.23 0.72, p=0.0013). The analysis of allelic frequency distributions showed Medical University Hospital, Taichung, that the G allele of PDCD6 rs4957014 decreased lung cancer susceptibility (p=0.0090). 4 Taiwan; Department of Respiratory There was no association between PDCD6 rs3756712 genotypes and lung cancer risk. Therapy, China Medical University, fi Taichung, Taiwan; 5Department of Interestingly, the GG genotype at PDCD6 rs4957014 signi cantly decreased the risk of Bioinformatics and Medical Engineering, lung cancer among males (adjusted OR =0.29, 95% CI =0.14–0.57) and smokers (adjusted Asia University, Taichung, Taiwan OR =0.34, 95% CI =0.18–0.61) but not among females and non-smokers. *These authors contributed equally to Conclusion: The GG genotype of PDCD6 rs4957014 may decrease lung cancer risk in this work males and smokers and may serve as a practical marker for early detection and the incidence of lung cancer in Taiwan. Keywords: genotype, lung cancer, male, programmed cell death 6 (PDCD6), polymorphism, smoking Introduction For decades, lung cancer has been the most commonly diagnosed cancer and the leading cause of cancer death all over the world.1–3 Although several anticancer therapeutic strategies and technologies are rapidly being developed, the prognosis of Correspondence: Da-Tian Bau; Chia-Wen lung cancer patients remains very poor, as the overall 5-year survival rates are still less Tsai 4,5 Terry Fox Cancer Research Laboratory, than 15–20%. From an epidemiological viewpoint, the most commonly identified Translational Medicine Research Center, factor in lung development and carcinogenesis is believed to be the individual’s long- China Medical University Hospital, 2 Yuh-Der Road, Taichung 404, Taiwan term history of tobacco consumption, which is also a useful predictor of poor Tel +886 42 205 3366 (Ext. 5805) prognosis.6–8 In this decade, many case-control studies have reported that specific Email [email protected]; [email protected] genotypes are associated with higher lung cancer risk for cigarette smokers than for submit your manuscript | www.dovepress.com OncoTargets and Therapy 2019:12 6237–6244 6237 DovePress © 2019 Shen et al. This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License (http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work http://doi.org/10.2147/OTT.S205544 you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms (https://www.dovepress.com/terms.php). Shen et al Dovepress non-smokers9–17 and vice versa.18–21 In 2010, Lissowska and Medical University Hospital. The clinical characteristics of colleagues conducted a meta-analysis of 41 global studies these lung cancer patients, including their histological details, and proposed that family lung cancer history, although often were all graded and definedbywell-traineddoctors.The not well recorded, is a risk factor for lung cancer.22 The exclusion criteria were history of any other cancer or pulmon- above studies elucidating the gene-lifestyle interactions in ary disease, such as chronic obstructive pulmonary disease, lung cancer risk, with or without attention to smoking status, pneumothorax, and asthma. Simultaneously, 716 healthy may provide not only predictive markers for revealing the volunteers without lung cancer for every case were chosen personalized etiology of lung cancer but also potential targets as controls by matching for age, gender, and smoking behavior for personalized therapy and genomic pharmacology. after initial random sampling from the Health Examination The PDCD6 gene, also known as apoptosis-linked gene 2 Cohort of China Medical University Hospital. The exclusion (ALG- 2), is located on human chromosome 5p15.33 and criteria of the controls included previous malignancy, metas- encodes the 22-kD programmed cell death protein 6.23,24 tasized cancer from another or an unknown origin, and any PDCD6 is a Ca2+-binding protein capable of interacting with genetic or familial diseases. All participants in this project Alix/AIP1 and their orthologs,25 ASK1,26 and Sec31A,27 so as voluntarily completed a self-administered questionnaire and to participate in T-cell receptor-, Fas-, glucocorticoid-, and ER provided a 5-ml sample of peripheral blood for genotyping. stress-induced apoptosis.23,28 In a knockout animal model, The study was conducted in accordance with the Declaration PDCD6-deficient mice were developmentally and immunolo- of Helsinki and approved by the Institutional Review Board of gically normal, indicating that PDCD6 is not essential for the China Medical University Hospital with the document physical development or immune function.29 However, coded DMR100-IRB-284. Written informed consent was PDCD6-deficient cells were no longer capable of blocking obtained from each participant with the help of the tissue apoptosis induced by TCR, FAS, or dexamethasone signals.29 bank. Typical characteristics of the subjects included in this The expression levels and genotypes30 of PDCD6 are asso- study are summarized in Table 1. ciated with cancer risk. In 2003, it was found that PDCD6 was upregulated at tumor sites relative to non-tumor sites among Methodology for PDCD6 genotyping lung cancer patients.31 With respect to lung cancer genomics, Genomic DNA from peripheral blood leucocytes of each only one paper has investigated the association of PDCD6 subject was extracted with a QIAamp Blood Mini Kit genotypes with lung cancer risk.32 In that study, the T allele of (Blossom, Taipei, Taiwan) and further stored and processed rs3756712 G/T, but not that of rs4957014 G/T, was found to be as previously described.16,17 Briefly, the polymerase chain associated with an increased risk of lung cancer.32 However, reaction (PCR) cycling programs set for PDCD6 genotypes the positive findings reported by them should be validated by were the following: one cycle at 94 °C for 5 min; 35 cycles of other studies, especially those conducted in Asian populations. 94 °C for 30 s, 55 °C for 30 s and 72 °C for 30 s; and a final Thus, in the present study, we aimed to investigate the con- extension at 72 °C for 10 min. The DNA sequences of the tribution of PDCD6 genotypes at rs3756712 G/T and forward and reverse primers for PDCD6 rs4957014 were 5′- rs4957014 G/T single-nucleotide polymorphic sites to the TGGTGTTTCATACCATTGACACTTGC-3′ and 5′- risk of lung cancer and then to examine the joint effect of CTCAGAACCAAGCAGGTTCCTTCA-3′,respectively. environmental factors, such as habitual smoking, and PDCD6 As for PDCD6 rs3756712, the DNA sequences of the for- genotypes on lung cancer risk in Taiwan. ward and reverse primers were 5′- TACAGTGGCAAAG GACCACA-3′ and 5′-CACATTCCAGCACTCACCAC-3′, respectively. Following PCR amplification, the products of Materials and methods PDCD6 rs4957014 and rs3756712 were subject to restriction Methodology for population data collection enzyme digestion with HphI and RsaI (New England First, we have evaluated the sample size for the study group BioLabs, Ipswich, MA, USA), respectively. As for PDCD6 and the estimated total sample size was 864 (432 in each rs4957014, the digestible G allele was cut into 113- and group) while alpha =5%, power =80%, the proportion of 13-base pair contigs, while the indigestible T allele was left homozygous mutant in the case group =10%, and the differ- intact as a 126-base pair long contig. As for PDCD6 ence =5%. From 2005 to 2008, data on 358 patients diagnosed rs3756712, the digestible G allele was cut into 113- and 13- with lung cancer were collected by the surgery team led