In this study, a random sample of 507 lung cancer patients (353 males and 154 females) was involved as well as 505 healthy control people (354 males and 151 females), with an average age of 60.75 ± 9.98 and 60.40 ± 7.39 (Table 1). There was no significant difference in gender and age distribution between the case group and the control group (p > 0.05). In addition, the characteristics of the study population were collected for subsequent studies, including body mass index (BMI), smoking and drinking history, pathological type, pathological stage, and lymph node metastasis (LNM).
Basic information of the selected SNPs
Four SNPs in CYP19A1 were genotyped among the subjects. The basic information of all candidate SNPs is listed in Table 2. All SNPs are located on chromosome 15 and in the different position of CYP19A1 gene. The deviation of Hardy-Weinberg equilibrium in the control group was evaluated, and the results showed that the candidate SNPs all met the expected p value (p > 0.05), and all SNPs satisfied further study. In addition, under the allele risk model, there was no significant difference in the distribution of alleles of each SNP between the lung cancer cases and the control group. (p > 0.05). Functional prediction of SNPs was conducted in HaploReg v4.1 database to explore their regulatory effect. The results showed that the four SNPs exhibited potential biological functions in gene regulation.
Genetic model analyses of the selected SNPs
Four genetic models analysis for the relationship between CYP19A1 polymorphism and risk of lung cancer are listed in Table 3. Our results revealed an association between rs28757157 and increased risk of lung cancer in the genotype model (OR = 1.33, 95% CI: 1.03-1.73, p = 0.032). Rs59429575 was also associated with an increased risk of lung cancer in recessive model (OR = 2.03, 95% CI: 1.00-4.11, p = 0.049).
In addition, we conducted a stratified analysis to explore the risk effects of these SNPS in specific groups of people. Stratified analysis of the clinical characteristics of rs28757157 polymorphism are shown in Table 4. The results indicated that rs28757157 heterozygote genotype (TC) was associated with increased susceptibility to lung cancer in people under 60 years of age (OR = 1.6, 95% CI: 1.09-2.35, p = 0.016). While the TT genotype of rs28757157 exerted a protective role in the development of lung cancer among people under 60 years and people with a BMI greater than 24.(age ≤ 60: OR = 0.11, 95% CI: 0.01-0.87, p = 0.036; BMI > 24: OR = 0.19, 95% CI: 0.04-0.87, p = 0.033). In addition, rs28757157 was identified as a genetic risk factor for lung cancer susceptibility in the allele, dominant, and additive models in the smoking population (allele model: OR = 1.48, 95% CI: 1.00-2.18, p = 0.048; dominant model: OR = 1.58, 95% CI: 1.01-2.47, p = 0.045; additive model: OR = 1.57, 95% CI: 1.03-2.4, p = 0.036).
Stratification analyses by clinical characteristics of the rs59429575 polymorphism are summarized in Table 5. Stratified analysis by gender demonstrated a remarkable relationship between enhanced lung cancer risk and the TT genotype of rs59429575 (OR = 5.18, 95% CI: 1.12-24.05, p = 0.036). In addition, in the patients with lung adenocarcinoma, rs59429575 was identified as a risk factor for lung cancer development (Homozygote: OR = 2.37, 95% CI: 1.01-5.56, p = 0.047; recessive model: OR = 2.55, 95% CI: 1.09-5.95, p = 0.03).