Mitochondria show the special role in cellular bioenergy and many essential physiological activities. Previous researches have suggested that variations of mitochondrial DNA copy number contribute to development of different types of carcinomas. However, the relationship of mtDNA copy number in peripheral blood leukocytes (PBLs) with the risk of head and neck squamous cell carcinoma (HNSCC) is still inconclusive. We investigated the association of mtDNA with HNSCC risk through a case–control study including 570 HNSCC cases and 597 cancer‐free controls. mtDNA copy number in PBLs was measured by real‐time qPCR. Logistic regression was performed to estimate the association between the mtDNA copy number in PBLs and HNSCC risk. A U‐shaped relation between the mtDNA copy number and HNSCC risk was found. Compared with those in the second quartile group, the adjusted odds ratios (ORs) and 95% confidence interval (CI) for those in the first and the forth quartile groups were 1.95 (1.37–2.76) and 2.16 (1.53–3.04), respectively. Using restricted cubic spline analysis, we confirmed such a significant U‐shaped relation. Furthermore, the U‐shaped association remained significant in different subgroups stratified by age, gender, tobacco smoking, and alcohol consumption. Both extremely low and high mtDNA copy numbers had significant associations with the increased HNSCC risk.

Genome-wide association studies (GWAS) have reported 45 single-nucleotide polymorphisms (SNPs) that may contribute to the susceptibility of lung cancer, with the majority in non-coding regions. However, no study has ever systematically evaluated the association between SNPs in physical chromatin interaction regions and lung cancer risk. In this study, we integrated the chromatin interaction information (Hi-C data) of lung cancer cell line and conducted a meta-analysis with two Asian GWASs (7,127 cases and 6,818 controls) to evaluate the association of potentially functional SNPs in chromatin interaction regions with lung cancer risk. We identified four novel lung cancer susceptibility loci located at 1q21.1 (rs17160062, P=4.00×10 -6 ), 2p23.3 (rs670343, P=4.87×10 -7 ), 2p15 (rs9309336, P=3.24×10 -6 ) and 17q21.2 (rs9252, P=1.51×10 -5 ) that were significantly associated with lung cancer risk after correction for multiple tests. Functional annotation result indicated that these SNPs may contribute to the development of lung cancer by affecting the availability of transcription factor binding sites. The HaploReg analysis suggested that rs9309336 may affect binding motif of transcription factor Foxp1. Expression quantitative trait loci analysis revealed that rs9309336 and rs17160062 could regulate the expressions of cancer-related genes (PUS10 and CHD1L). Our results revealed that variants in chromatin interaction regions could contribute to the development of lung cancer by regulating the expression of target genes, which providing novel implications for the understanding of functional variants in the development of lung cancer.

Autophagy is an essential process to maintain cellular homeostasis and functions, which has been demonstrated to play an important role in the different stages of tumorigenesis. To evaluate whether the genetic variants in autophagy-related genes influence the head and neck squamous cell carcinoma (HNSCC) risk, we conducted a case-control study to analyze 11 tagging single nucleotide polymorphisms (SNPs) of three core autophagosome formation genes (ATG5, ATG12, and ATG16L1) with 576 HNSCC cases and 1552 healthy controls among Chinese population. Finally, we identified that rs26537 of ATG12 (additive model: adjusted odds ratio [OR] = 1.19, 95% confidence interval [CI] = 1.03-1.37, P = 0.017) and rs4663402 in ATG16L1 (additive model: adjusted OR = 1.39, 95%CI = 1.08-1.80, P = 0.010) were significantly associated with the increased risk of HNSCC. However, no association was detected between other SNPs and HNSCC risk. The results of expression quantitative trait loci (eQTL) analysis based on Genotype-Tissue Expression (GTEx) accessible data, showed that the risk allele of rs26537 was significantly associated with up-regulated expression of ATG12 (P = 0.0021). Further luciferase activity assay indicated that rs26537 T > C in ATG12 intron one region significantly enhanced transcription activity. These results suggested that ATG12 eQTL SNP rs26537 might contribute to an allele-specific effect on the expression of host gene ATG12 and explain a fraction of HNSCC genetic susceptibility.

BackgroundSquamous cell carcinoma of the head and neck (SCCHN) is one of the most common cancers worldwide and includes cancers arising from the oral cavity, pharynx and larynx. Genome-wide association studies have found several genetic variants related to the risk of SCCHN; however, they could only explain a small fraction of the heritability. Thus, more susceptibility loci associated with SCCHN need to be identified.MethodsAn association study was conducted by genotyping 555 patients with SCCHN and 1367 controls in a Chinese population. Single-variant association analysis was conducted on 63 373 SNPs, and the promising variants were then confirmed by a two-stage validation with 1875 SCCHN cases and 4637 controls. Bioinformatics analysis and functional assays were applied to uncover the potential pathogenic mechanism of the promising variants and genes associated with SCCHN.ResultsWe first identified three novel genetic variants significantly associated with the risk of SCCHN (p=7.45×10−7 for rs2517611 at 6p22.1, p=1.76×10−9 for rs2524182 at 6p21.33 and p=2.17×10−10 for rs3131018 at 6p21.33). Further analysis and biochemical assays showed that rs3094187, which was in a region in high linkage disequilibrium with rs3131018, could modify TCF19 expression by regulating the binding affinity of the transcription factor SREBF1 to the promoter of TCF19. In addition, experiments revealed that the inhibition of TCF19 may affect several important pathways involved in tumourigenesis and attenuate the cell proliferation and migration of SCCHN.ConclusionThese findings offer important evidence that functional genetic variants could contribute to development of SCCHN and that TCF19 may function as a putative susceptibility gene for SCCHN.

Background: As the sixth most common cancer of worldwide, head and neck cancers (HNC) are springing from oral cavity, pharynx and larynx and there is no strong biomarker for prognosis. Rates of 5 years survival with HNC remain relatively low in decades with improvement of treatments. Evidence that single nucleotide polymorphisms (SNPs) play a part in cancer prognosis is growing. Methods: We conducted an exome-wide association study among 261 patients with head and neck squamous cell carcinoma (HNSCC) and then validated in The Cancer Genome Atlas (TCGA) database for survival by using the Cox proportional hazards regression models and Kaplan-Meier analyses. Results: After combining the result of the two stages, 4 SNPs were significantly associated with HNSCC survival (rs16879870 at 6q14.