Interleukin-10 haplotype may predict survival and relapse in resected non-small cell lung cancer.

IL-10 is associated with tumor malignancy via immune escape. We hypothesized that IL-10 haplotypes categorized by IL-10 promoter polymorphisms at -1082A>G, -819C>T, and -592C>A might influence IL-10 expression and give rise to non-small cell lung cancer (NSCLC) patients with poor outcomes and relapse. We collected adjacent normal tissues from 385 NSCLC patients to determine IL-10 haplotypes by direct sequencing and polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Of the 385 tumors, 241 were available to evaluate IL-10 mRNA expression levels by real-time RT-PCR. The influence of IL-10 haplotypes on overall survival (OS) and relapse free survival (RFS) were determined by Kaplan-Meier and multivariate Cox regression analysis. The results showed that IL-10 mRNA levels were significantly higher in tumors with the non-ATA haplotype than with the ATA haplotype (P = 0.004). Patients with the non-ATA haplotype had shorter OS and RFS periods than did patients with the ATA haplotype. This may be associated with the observation that the number of tumor-infiltrating lymphocytes was decreased in the tumors with higher levels of IL-10. Consistently, T cells from the peripheral blood of the patients with non-ATA haplotype were more susceptible to apoptosis and less cytotoxic to tumor cells, compared to those from the patients with ATA haplotype. The results suggest that IL-10 can promote tumor malignancy via promoting T cell apoptosis and tumor cell survival, and IL-10 haplotype evaluated by PCR-RFLP or direct sequencing may be used to predict survival and relapse in resected NSCLC, helping clinicians to make appropriate decisions on treatment of the patients.

Associations of MDM2 SNP309, transcriptional activity, mRNA expression, and survival in stage I non-small-cell lung cancer patients with wild-type p53 tumors.

BACKGROUND: Mouse double minute 2 (MDM2) is a negative regulator of p53. In the present study, we examined MDM2 transcriptional activity and messenger RNA (mRNA) expression in lung tumors with respect to MDM2 SNP309 genotypes and p53 mutation status, and the effects of MDM2 SNP309 genotypes and p53 mutation status on lung cancer prognosis. METHODS: p53-null lung cancer cells were cotransfected with MDM2 P2 reporter construct containing the TT or GG genotype and wild-type or mutant p53 plasmids for luciferase reporter assay. Genomic DNA from 306 lung tumors and adjacent normal tissues was used to determine p53 mutation and MDM2 genotype by direct sequencing and polymerase chain reaction (PCR) restriction fragment length polymorphism. Real-time reverse-transcriptase PCR was applied to determine MDM2 mRNA levels. Overall survival was also calculated. RESULTS: Transcriptional activity of the MDM2 promoter containing the SNP309 GG genotype was significantly lower than that containing the TT genotype in p53-null lung cancer cells cotransfected with wild-type p53 expression plasmid under mithramycin A treatment. MDM2 mRNA levels in tumors with the SNP309 TG and GG genotypes were higher than those in tumors with the TT genotype, particularly in wild-type p53 tumors. Stage I patients with MDM2 SNP309 GG also had better overall survival than TT carriers, especially wild-type p53 patients (hazard ratio = 0.34; 95% confidence interval 0.15-0.80). Similar results were not observed in late-stage patients. CONCLUSIONS: MDM2 SNP309 was associated with MDM2 transcripts, mRNA levels, and survival in stage I non-small-cell lung cancer patients with wild-type p53 tumors.

Potential increase in the prognostic value of p53 mutation by Pro72 allele in stage I non-small-cell lung cancer.

BACKGROUND: Accumulated evidence suggests that p53 function altered by its gene mutation or genetic polymorphism contributes to tumor malignancy. Association of p53 mutation and its codon 72 polymorphism with lung cancer prognosis has been extensively studied. However, the joint effect of p53 mutation and p53 codon 72 polymorphism on lung cancer prognosis remains uncertain. METHODS: In the present study, 266 primary lung cancer patients were included and overall survival was calculated. Genomic DNA prepared from adjacent normal lung and lung tumor tissues was used to determine p53 codon 72 genotype and p53 mutation by polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) and direct sequencing, respectively. RESULTS: For all stages, neither p53 codon 72 genotype nor p53 mutation is associated with lung cancer prognosis. However, stage I patients with p53 mutation had a 1.79-fold hazard ratio [95% confidence interval (CI) 1.04-3.10] for overall survival when compared with p53 wild-type patients. Notably, stage I patients with p53 mutation and p53 codon 72 Pro/Pro genotype experienced a 2.66-fold hazard ratio (95% CI 1.21-5.85) for overall survival when compared with those with p53 wild-type and Arg/Arg genotype. An increased prognostic value was not observed in stage I patients with p53 wild-type and p53 Pro72 allele or in those with p53 mutation and p53 codon 72 Arg/Arg genotype. CONCLUSIONS: We therefore suggest that p53 codon 72 Pro allele potentially increases the prognostic value of p53 mutation in stage I non-small-cell lung cancer.

NAT2 fast acetylator genotype and MGMT promoter methylation may contribute to gender difference in K-RAS mutation occurrence in Taiwanese colorectal cancer.

A recent study conducted by our group showed that the NAT2 fast acetylator genotype is associated with an increasing risk for the development of colorectal cancer (CRC), especially for females. We therefore examined whether a higher risk of CRC in females with the NAT2 fast acetylator genotype was associated with the occurrence of K-RAS mutation, and to further verify whether MGMT promoter methylation was linked to the occurrence of K-RAS mutation in patients with the NAT2 fast acetylator genotype. Herein, 151 CRC cases were examined for NAT2 genetic polymorphisms and MGMT promoter methylation by PCR-RFLP and methylation-specific PCR (MSP). The results of this study show that the NAT2 fast acetylator genotype is associated with the occurrence of K-RAS mutation in female cases (OR = 4.820, 95% CI = 1.113-20.873), but not associated with MGMT promoter methylation. Surprisingly, MGMT promoter methylation significantly deepens the impact of NAT2 fast acetylation on K-RAS mutation in the female cases (OR = 5.129, 95% CI = 1.092-24.105). In conclusion, Taiwanese women with the NAT2 fast acetylator genotype may exhibit a higher risk of CRC with increased occurrence of K-RAS mutation. Detection of NAT2 genotypes and MGMT promoter methylation may be useful in the risk assessment for CRC in Taiwanese women.

NAT2 fast acetylator genotype is associated with an increased risk of colorectal cancer in Taiwan.

In Taiwan, colorectal cancer has one of the highest rates of increased incidence in the past two decades. Heterocyclic amines from dietary cooked meats are metabolically activated by NAT2 (N-acetyltransferase 2), which are associated with colorectal cancer incidence. Thus, the NAT2 fast acetylator genotype may be associated with colorectal cancer risk. However, the association between the NAT2 genotype and colorectal cancer risk is not clearly understood. We conducted a study with 244 primary colorectal cancer cases and 299 cancer-free healthy control subjects to verify the association of NAT2 polymorphisms with the risk of Taiwanese colorectal cancer. Our data showed that subjects with the NAT2 W/W homozygous genotype had a 1.63-fold increased risk of colorectal cancer compared with those with the Mx/Mx slow acetylator genotype (95 percent confidence interval, 1.03-2.58); however, no risk was found in the W/Mx heterozygous and Mx/W+W/W fast acetylator genotypes. Being stratified by gender factors, the colorectal cancer risk in females with homozygous W/W or Mx/W+W/W fast acetylators increased 2.47-fold and 2.13-fold compared with those with the Mx/Mx slow acetylator genotype (95 percent confidence interval, 1.27-4.82 for W/W genotype; 95 percent confidence interval, 1.17-3.89 for Mx/W+W/W genotype); however, the risk of the NAT2 genotype and colorectal cancer was not observed in males. Collectively, patients with the NAT2 fast acetylator genotype were more prone to colorectal cancer and reflected the possibility that exposure to heterocyclic amines may contribute to colorectal cancer development in Taiwan, especially in Taiwanese females.

NAT2 fast acetylator genotype is associated with an increased risk of lung cancer among never-smoking women in Taiwan.

The correlation between cooking oil fumes, containing relatively higher amounts of heterocyclic amines, and female lung cancer has been revealed. The association of genetic polymorphisms of CYP1A2 and NAT2, two major enzymes responsible for the metabolism of heterocyclic amines, with lung cancer has been investigated with inconclusive results. In this study targeted on never-smoking population with 162 lung cancer patients and 208 non-cancer controls, while the distributions of CYP1A2 phenotypes in lung cancer patients were comparable to that in controls, NAT2 fast acetylators had an OR of 2.44 (95% CI 1.40-4.23, P=0.002) and 2.56 (95% CI 1.37-4.80, P=0.003) for lung cancer in overall and female cases, respectively, but not in males. These results suggested never-smoking females with NAT2 fast acetylator were more prone to lung cancer and reflected the possibility that exposure to heterocyclic amines may contribute to the female lung cancer development in Taiwan.