title: Genetic Features of Aflatoxin-Associated Hepatocellular Carcinoma.
abstract: Dietary exposure to aflatoxin is an important risk factor for hepatocellular carcinoma (HCC). However, little is known about the genomic features and mutations of aflatoxin-associated HCCs compared with HCCs not associated with aflatoxin exposure. We investigated the genetic features of aflatoxin-associated HCC that can be used to differentiate them from HCCs not associated with this carcinogen.
  
  
  
  We obtained HCC tumor tissues and matched non-tumor liver tissues from 49 patients, collected from 1990 through 2016, at the Qidong Liver Cancer Hospital Institute in China-a high-risk region for aflatoxin exposure (38.2% of food samples test positive for aflatoxin contamination). Somatic variants were identified using GATK Best Practices Pipeline. We validated part of the mutations from whole-genome sequencing and whole-exome sequencing by Sanger sequencing. We also analyzed genomes of 1072 HCCs, obtained from 5 datasets from China, the United States, France, and Japan. Mutations in 49 aflatoxin-associated HCCs and 1072 HCCs from other regions were analyzed using the Wellcome Trust Sanger Institute mutational signatures framework with non-negative matrix factorization. The mutation landscape and mutational signatures from the aflatoxin-associated HCC and HCC samples from general population were compared. We identified genetic features of aflatoxin-associated HCC, and used these to identify aflatoxin-associated HCCs in datasets from other regions. Tumor samples were analyzed by immunohistochemistry to determine microvessel density and levels of CD34 and CD274 (PD-L1).
  
  
  
  Aflatoxin-associated HCCs frequently contained C>A transversions, the sequence motif GCN, and strand bias. In addition to previously reported mutations in TP53, we found frequent mutations in the adhesion G protein-coupled receptor B1 gene (ADGRB1), which were associated with increased capillary density of tumor tissue. Aflatoxin-associated HCC tissues contained high-level potential mutation-associated neoantigens, and many infiltrating lymphocytes and tumors cells that expressed PD-L1, compared to HCCs not associated with aflatoxin. Of the HCCs from China, 9.8% contained the aflatoxin-associated genetic features, whereas 0.4%-3.5% of HCCs from other regions contained these genetic features.
  
  
  
  We identified specific genetic and mutation features of HCCs associated with aflatoxin exposure, including mutations in ADGRB1, compared to HCCs from general populations. We associated these mutations with increased vascularization and expression of PD-L1 in HCC tissues. These findings might be used to identify patients with HCC due to aflatoxin exposure, and select therapies.
authors.affiliation: State Key Lab of Molecular Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College; Collaborative Innovation Center for Cancer Medicine; Third Hospital, Peking University, Beijing, China.
authors.forename: Weilong
authors.initials: W
authors.lastname: Zhang
authors.affiliation: State Key Lab of Molecular Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Huan
authors.initials: H
authors.lastname: He
authors.affiliation: State Key Lab of Molecular Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Mengya
authors.initials: M
authors.lastname: Zang
authors.affiliation: State Key Lab of Molecular Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Qifeng
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Department of Abdominal Surgical Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Qidong People's Hospital and Qidong Liver Cancer Institute, Qidong, Jiangsu Province, China.
authors.forename: Ling-Ling
authors.initials: LL
authors.lastname: Lu
authors.affiliation: Department of Pathology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Peiqing
authors.initials: P
authors.lastname: Ma
authors.affiliation: Qidong People's Hospital and Qidong Liver Cancer Institute, Qidong, Jiangsu Province, China.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Zheng
authors.affiliation: Qidong People's Hospital and Qidong Liver Cancer Institute, Qidong, Jiangsu Province, China.
authors.forename: Nengjin
authors.initials: N
authors.lastname: Wang
authors.affiliation: State Key Lab of Molecular Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Lab of Molecular Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Siyuan
authors.initials: S
authors.lastname: He
authors.affiliation: State Key Lab of Molecular Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Chen
authors.affiliation: State Key Lab of Molecular Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.
authors.forename: Xiaoyue
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Abdominal Surgical Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Jianqiang
authors.initials: J
authors.lastname: Cai
authors.affiliation: State Key Lab of Molecular Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Liu
authors.affiliation: State Key Lab of Molecular Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Zongtang
authors.initials: Z
authors.lastname: Sun
authors.affiliation: National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China; Department of Experimental Research, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong Province, China. Electronic address: zengyx@sysucc.org.cn.
authors.forename: Yi-Xin
authors.initials: YX
authors.lastname: Zeng
authors.affiliation: State Key Lab of Molecular Oncology, Immunology Department, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical Colleges, Beijing, China. Electronic address: quchf@cicams.ac.cn.
authors.forename: Chunfeng
authors.initials: C
authors.lastname: Qu
authors.affiliation: State Key Lab of Molecular Oncology, Laboratory of Cell and Molecular Biology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College; Collaborative Innovation Center for Cancer Medicine, Beijing, China. Electronic address: jiaoyuchen@cicams.ac.cn.
authors.forename: Yuchen
authors.initials: Y
authors.lastname: Jiao
mesh_terms: D000348:Aflatoxins / Q000633:toxicity*; D042501:Angiogenic Proteins / Q000235:genetics*; D018952:Antigens, CD34 / Q000032:analysis; D060890:B7-H1 Antigen / Q000032:analysis*; D002273:Carcinogens / Q000633:toxicity; D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000139:chemically induced / Q000737:chemistry / Q000235:genetics*; D004252:DNA Mutational Analysis; D059472:Exome / Q000235:genetics; D006801:Humans; D008113:Liver Neoplasms / Q000098:blood supply / Q000139:chemically induced / Q000737:chemistry / Q000235:genetics*; D016246:Lymphocytes, Tumor-Infiltrating / Q000737:chemistry; D055806:Microvessels; D009154:Mutation; D043562:Receptors, G-Protein-Coupled; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
chemical_list: C468226:ADGRB1 protein, human; D000348:Aflatoxins; D042501:Angiogenic Proteins; D018952:Antigens, CD34; D060890:B7-H1 Antigen; D002273:Carcinogens; D043562:Receptors, G-Protein-Coupled; D016159:Tumor Suppressor Protein p53
keywords: Aspergillus; Liver Cancer; Pathogenesis; Risk Factor