Chen JH, Wang YY, Lv WB, Gan Y, Chang W, Tian NN, Huang XH, Liu L, Yu XF, Chen SD. Effects of interactions between environmental factors and KIF1B genetic variants on the risk of hepatocellular carcinoma in a Chinese cohort. World J Gastroenterol 2016; 22(16): 4183-4190 [PMID: 27122668 DOI: 10.3748/wjg.v22.i16.4183]
Corresponding Author of This Article
Dr. Si-Dong Chen, Professor, Department of Epidemiology, School of Public Health and Tropical Medicine, Southern Medical University, No. 1838, North Guangzhou Avenue, Guangzhou 510515, Guangdong Province, China. chensidong1@126.com
Research Domain of This Article
Gastroenterology & Hepatology
Article-Type of This Article
Case Control Study
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Jun-Hu Chen, Wei Chang, Si-Dong Chen, Department of Epidemiology, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou 510515, Guangdong Province, China
Jun-Hu Chen, Li Liu, Yu Gan, Wei Chang, Na-Na Tian, Xiao-Hui Huang, Si-Dong Chen, Department of Epidemiology and Biostatistics, School of Public Health, Guangdong Pharmaceutical University, Guangzhou 510310, Guangdong Province, China
Yan-Yan Wang, Department of Obstetrics and Gynecology, Affiliated HouJie Hospital of Guangdong Medical College, Dongguan 523945, Guangdong Province, China
Wei-Biao Lv, Xin-Fa Yu, Department of Oncology, The First People’s Hospital of Shunde, Foshan 528300, Guangdong Province, China
ORCID number: $[AuthorORCIDs]
Author contributions: Chen JH and Liu L analyzed the data and wrote the manuscript; Chang W, Tian NN, and Lv WB collected materials and clinical data; Wang YY, Gan Y, and Huang XH performed the experiments; Yu XF and Chen SD conceived and designed the study.
Institutional review board statement: This study was reviewed and approved by the Ethics Committee of the First People’s Hospital of Shunde, Foshan, China.
Informed consent statement: All study participants provided informed written consent prior to study enrollment.
Conflict-of-interest statement: The authors declare that they have no conflicts of interest related to this work.
Data sharing statement: Technical appendix, statistical code, and dataset are available from the corresponding author at chensidong1@126.com.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Dr. Si-Dong Chen, Professor, Department of Epidemiology, School of Public Health and Tropical Medicine, Southern Medical University, No. 1838, North Guangzhou Avenue, Guangzhou 510515, Guangdong Province, China. chensidong1@126.com
Telephone: +86-20-34055180 Fax: +86-20-34055355
Received: December 25, 2015 Peer-review started: December 28, 2015 First decision: December 30, 2015 Revised: January 17, 2016 Accepted: February 20, 2016 Article in press: February 23, 2016 Published online: April 28, 2016 Processing time: 115 Days and 19.5 Hours
Abstract
AIM: To examine the effect of the potential interaction between KIF1B variants (rs17401966 and rs3748578) and environmental factors on the risk of hepatocellular carcinoma (HCC) in a high-risk region in China.
METHODS: Three hundred and six patients with HCC and 306 hospital-based control participants residing in the Shunde region of Guangdong Province, China were enrolled. Clinical characteristics were collected by reviewing the complete medical histories from the patient archives, and epidemiological data were collected using a questionnaire and clinical examination. Two single nucleotide polymorphisms (SNPs) of KIF1B (rs17401966 and rs3748578) were chosen for the current study. All subjects were genotyped using a TaqMan real-time polymerase chain reaction. Multiplicative and additive logistic regression models were used to evaluate various gene-environment interactions.
RESULTS: Smoking, frequent consumption of raw freshwater fish, hepatitis B virus (HBV) infection, and a family history of HCC were important risk factors for HCC in this population. Chronic infection with HBV was the most important environmental risk factor for HCC [odds ratio (OR) = 12.02; 95% confidence interval (95%CI): 6.02-24.00]. No significant association was found between the KIF1B variants alone and the risk of HCC. Nevertheless, a significant additive effect modification was observed between rs17401966 and alcohol consumption (P for additive interaction = 0.0382). Compared with non-drinkers carrying either the AG or GG genotype of rs17401966, individuals classified as alcohol consumers with the AA genotype of rs17401966 had a significantly increased risk of HCC (OR = 2.36; 95%CI: 1.49-3.74).
CONCLUSION: The gene-environment interaction between the KIF1B rs17401966 variant and alcohol consumption may contribute to the development of HCC in Chinese individuals.
Core tip:KIF1B has been proposed as a promising susceptibility gene for hepatocellular carcinoma (HCC) by a recent genome-wide association study (GWAS) in Chinese populations. However, the most significant variant (rs17401966) in this GWAS yielded inconsistent results in subsequent replication studies. In this work, we evaluated the role of rs17401966 in genetic susceptibility to HCC and gene-environment interactions. Our study demonstrates that the gene-environment interaction between the KIF1B rs17401966 variant and drinking alcohol significantly contributed to the development of HCC in the Chinese population.
Citation: Chen JH, Wang YY, Lv WB, Gan Y, Chang W, Tian NN, Huang XH, Liu L, Yu XF, Chen SD. Effects of interactions between environmental factors and KIF1B genetic variants on the risk of hepatocellular carcinoma in a Chinese cohort. World J Gastroenterol 2016; 22(16): 4183-4190
Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. HCC ranks as the fifth most common cancer in men and seventh most common cancer in women[1]. Eastern Asia experiences a large burden of the geographical distribution of HCC; China alone accounts for approximately 55% of all HCC cases worldwide[2]. Prognosis of HCC patients is poor, with an average 3-year survival rate of 13%-21%[3,4]. Due to the high disease burden worldwide, it is important to identify individuals who are at a higher risk of HCC and to identify risk factors that may be modifiable. Several environmental factors that increase the risk of HCC have been found, including chronic infection with hepatitis B virus (HBV) or hepatitis C virus (HCV), exposure to aflatoxin, and consumption of alcohol[5-7].
However, only a small percentage of individuals who are exposed to these risk factors will eventually develop HCC, highlighting that genetic susceptibility is another factor for the development of HCC. HCC involves a complex interplay of multiple genetic and environmental factors[8]. However, underlying genetic mechanisms of hepatocellular carcinogenesis have not yet been fully elucidated.
Kinesin superfamily proteins (KIFs) make up a large gene family of microtubule motor proteins[9]. KIF1B, a member of the KIF family, maps to a gene locus at 1p36.22 and encodes two alternatively spliced isoforms, KIF1Bα and KIF1Bβ; both isoforms form homodimers and transport mitochondria and synaptic vesicle precursors, respectively. It has been postulated that KIF1B acts as a tumor suppressor. Downregulation of KIFs has been shown to contribute to tumorigenesis of certain cancers, including brain, colon and breast cancers[10]. Recently, Zhang et al[11] performed a genome-wide association study (GWAS) and found that KIF1B is a promising susceptibility gene for HCC in five independent Chinese populations. In this GWAS, the most significant variant of KIF1B (rs17401966), located in the intron of the gene, was associated with a decreased risk of HCC [joint odds ratio (OR) = 0.61, P = 1.7 × 10-18]. However, more recent studies have not drawn the same conclusion. Al-Qahtani et al[12] reported no significant association between the rs17401966 variant of KIF1B and HBV-related HCC. Sawai et al[13] also showed no association between rs17401966 and HBV-related HCC in a Japanese cohort. These inconsistent results may partly be due to the distinct genetic architecture among the different study populations. Additionally, the significant findings obtained by Zhang et al[11] may have resulted from a phenomenon known as the “winner’s curse,” where the odds ratio of the candidate variant is overestimated in the population, leading to reporting a positive result[14]. Another reason for the discrepancy among studies could be the complex gene-environment interactions involved in the development of HCC that have been neglected. Hence, we conducted a case-control study with HCC patients and hospital-based controls to clarify the effect of rs17401966 in KIF1B on HCC. In addition, one single nucleotide polymorphism (SNP), rs3748578, was in strong linkage disequilibrium (LD) with rs17401966[15], which was also associated with HBV-induced HCC. We also investigated the potential functional role of this variant rs3748578. We applied both additive and multiplicative models using a logistic regression analysis framework to assess the potential interactions between the variants and environmental factors in development of HCC in a Chinese cohort.
MATERIALS AND METHODS
Study population
Three hundred and six patients with HCC and 306 control patients were recruited from Shunde First People’s Hospital (Foshan, China) from October 2010 to October 2012. A diagnosis of HCC was made through a combination of liver function tests, serum immunological markers, liver ultrasonography (US) or computed tomography (CT), and pathological confirmation. Patients were excluded if they were diagnosed with cancer other than HCC after the workup. Age and sex-matched control participants with no history of cancer were enrolled from the hospital at the same time as case enrollment. Clinical characteristics were collected by reviewing the complete medical histories from the patient archives, including age, gender, serum α-fetoprotein (AFP) levels, hepatitis B surface antigen (HBsAg) status, HBV-DNA titer, alanine aminotransferase (ALT) levels, aspartate aminotransferase (AST) levels, and total bilirubin levels. Chronic infection with hepatitis B virus (CHB) was diagnosed based on HBsAg seropositivity, positive serum HBV-DNA levels, and continuously elevated ALT over a period of 6 mo.
Epidemiological data were collected using a questionnaire and clinical examination. The main definitions of risk categories were as follows: (1) a cigarette smoker is a person who smokes one or more cigarettes per day for at least 6 mo; (2) an alcohol drinker is a person who consumes beer, wine, or hard liquor at least once weekly for at least 6 mo during their lifetime; and (3) a family history of cancer in the first degree relatives (parents, siblings, and children). Written informed consent was obtained from all subjects. The study was approved by the Ethics Committee of the First People’s Hospital of Shunde.
Genetic variant genotyping
As previously described, rs1740966 variant was found to be the most significant HCC-associated variant with another candidate variant, rs3748578, in high-linkage to rs1740966. Zhang et al[15] predicted that both rs1740966 and rs3748578 may function in HCC tumor suppression. Therefore, we chose two SNPs (rs17401966 and rs3748578) of KIF1B for the current study.
DNA was extracted using the TIANamp Blood DNA Kit (Tiangen, Beijing, China) according to the manufacturer’s protocol. Genomic DNA was extracted from peripheral whole blood. All subjects were genotyped using TaqMan real-time polymerase chain reaction (Applied Biosystems, Foster City, CA, United States) without knowledge of subjects’ infection status. Samples were heated to 95 °C for 10 min followed by 45 cycles of 95 °C for 15 s and 60 °C for 1 min. The ABI Prism 7900HT Sequence Detection System (Applied Biosystems, Carlsbad, CA, United States) was used to analyze the endpoint fluorescence. To ensure the accuracy of genotyping, > 5% of the samples were randomly selected and repeated, yielding a 100% concordance.
Statistical analysis
Differences in the distribution of demographic characteristics, lifestyles, and HBV infection status between cases and controls were evaluated using χ2 test and t test, where appropriate. Hardy-Weinberg equilibrium (HWE) was tested for the genetic variants in controls. Logistic regressions were used to estimate the associations of environmental factors with HCC and ORs and corresponding 95% confidence intervals (CIs) were calculated. Logistic regressions were also fit to explore associations of genetic variants and HCC, taking into account both dominant and recessive inheritance patterns. Potential gene-environment interactions were studied using a logistic regression framework that employed both multiplicative and additive interaction models with a bootstrapping procedure. All statistical analyses were conducted using Stata software, version 14.0 (College Station, TX, United States). All probability analyses were two-sided tests where a P value < 0.05 was considered statistically significant.
RESULTS
A total of 306 patients with HCC (264 males and 42 females) and 306 controls (264 males and 42 females) were enrolled in the study with a mean age (± standard deviation) of 55.84 (± 11.49) and 55.83 (± 11.67) years, respectively. The general characteristics of the subjects are presented in Table 1. No significant differences were found between healthy controls and patients with HCC with regard to age and gender (P = 0.992 and P = 0.998, respectively). Logistic regression analysis suggested that smoking, frequent consumption of raw freshwater fish, HBV infection, and family history of HCC were important risk factors for HCC in the Shunde region of China (Table 1).
Table 1 Distribution of selected characteristics and environmental factors in hepatocellular carcinoma cases and controls n (%).
The genotypic distributions of rs3748578 and rs17401966 did not differ significantly between the cases and controls (Table 2). Logistic regression analysis failed to show a significant association between HCC with either rs3748578 or rs17401966 for all genetic models (Table 3).
Table 2 Distribution of rs3748578 and rs17401966 in hepatocellular carcinoma cases and controls n (%).
Variants
Genotypes
Case (n = 306)
Control (n = 306)
χ2
P value
HWE
rs3748578
GG
169 (55.22)
150 (49.02)
AG
122 (39.87)
138 (45.10)
AA
15 (4.91)
18 (5.88)
2.39
0.303
0.058
rs17401966
AA
159 (51.96)
150 (49.02)
AG
126 (41.18)
138 (45.10)
GG
21 (6.86)
18 (5.88)
1.04
0.595
0.058
Table 3 Association analysis between KIF1B variants and risk of hepatocellular carcinoma development n (%).
Tables 4 and 5 show the results of additive and multiplicative interaction analysis between the two variants and the main environmental risk factors for HCC. A significant additive interaction was seen between rs17401966 and alcohol consumption (P = 0.0382). Compared with non-drinkers carrying the rs17401966 AG or GG genotype, individuals who consumed alcohol and carried the AA genotype had a significantly increased risk of HCC, with an adjusted OR of 2.36 (95%CI: 1.49-3.74, P = 0.0382). No significant interactions were observed between the rs3748578 variant and environmental factors.
Table 4 Interaction analysis between rs3748578 and environmental factors in hepatocellular carcinoma development.
rs17401966 and history of raw freshwater fish eating
0.470
0.852
AG + GG
No
53
88
1.00
AA
No
58
83
1.16
0.72-1.87
AG + GG
Yes
94
68
2.30
1.45-3.64
AA
Yes
101
67
2.50
1.58-3.96
rs17401966 and history of chronic hepatitis B virus infection
0.269
0.753
AG + GG
No
32
126
1.00
AA
No
45
126
1.41
0.84-2.36
AG + GG
Yes
115
30
15.09
8.63-26.39
AA
Yes
114
24
18.7
10.40-33.63
rs17401966 and family history of hepatoma
0.697
0.524
AG + GG
No
125
152
1.00
AA
No
128
142
1.10
0.78-1.53
AG + GG
Yes
22
4
6.69
2.25-19.92
AA
Yes
31
8
4.71
2.09-10.62
DISCUSSION
The current study aimed to investigate whether two variants of KIF1B (rs17401966 and rs3748578) interacted with environmental risk factors of HCC to influence the risk of HCC. A significant additive interaction was observed between rs17401966 and alcohol consumption.
HCC is a complex disease associated with many risk factors and cofactors[16]. The major risk factor for HCC in China is clearly chronic HBV infection[17], with an 8%-20% prevalence of HBV[18] and approximately 93 million chronic HBV carriers[19]. The proportion of HBV-positive HCC has significantly increased, with 76% of HCC cases being HBV positive[20], which was consistent with 74.84% in our research. However, compared to China, the proportion of HCV-positive HCC was high in the United States, Italy, Japan, Brazil, Taiwan, Egypt, and other countries[20]. As we know, HCV prevalence in China is low (< 1.5%)[21], which is transmitted primarily through intravenous drug use and invasive medical treatment, particularly hemodialysis[22]. The overall prevalence of anti-HCV antibody (anti-HCV) in Guangdong Province was about 0.50%[23-25], after the implementation of strict blood screening and other procedural measures, and we did not describe the relationship between HCV and HCC in the research.
In this study, we did not find a significant association between rs17401966 and HCC. This result is not consistent with the results reported in the GWAS study by Zhang et al[11]. One possible explanation for this discrepancy is the fact that the study samples were made up of individuals with different genetic architectures, who were from south China and Japan. Additionally, according to evolutionary theory, individual common variants often exert modest effects on common diseases[26]. In other words, sufficient statistical power to detect a disease with low penetrance due to a specific variant would require enrollment of thousands of subjects in the study. A recent meta-analysis of rs17401966 and HCC summarized data from 7596 HCC cases and 9614 controls; this meta-analysis supported Zhang et al’s[15] findings, indicating a significant association between rs17401966 and HCC. Nevertheless, according to the common disease-common variant (CDCV) hypothesis, cumulative effects of multiple common variants or their interactions with environment factors underlie common diseases. The finding in the present study on the interaction between rs17401966 and alcohol consumption fits the CDCV hypothesis. Zhang et al[11] suggested a significant association between rs17401966 genotypes and expression of KIF1B in liver tissues, with carriers of the G allele having a greater KIF1B level than individuals without G allele (AA carriers). However, several studies have found that the G allele of rs17401966 demonstrated a protective effect on the susceptibility to HCC[27-29]. This inconsistency might be attributed to the fact that there were heterogeneous population structures. It is necessary to investigate the exact effect of ethnicity on the association between KIF1B polymorphisms and HCC risk in future. It has been hypothesized that KIF1B can act as a tumor suppressor. The mechanism by which this occurs is still unclear, but KIF1B may induce apoptosis by acting downstream of EglN3 prolyl hydroxylase[30], ultimately leading to inhibition of malignant transformation and progression.
Alcohol consumption is common in Guangdong Province, where the total drinking rate is 33.3%[31], with the region of Shunde having an even higher rate, especially in residents who habitually drink brewed Chinese rice wine[32]. Ethanol, the active compound in alcoholic beverages, is metabolized to acetaldehyde, which has been found to be mutagenic and carcinogenic[33,34], and other studies reported that alcohol was involved in hepatocarcinogenesis[35,36]. Therefore, a significant joint effect and interaction between rs17401966 and alcohol consumption was observed, suggesting that gene-environment interactions may provide further insights for comprehensive understanding of HCC in the Shunde area.
Our study is not without limitations. Hospital-based samples may lead to a selection bias of participants. Secondly, the sample size was limited and statistical power was insufficient for detection of a modest effect size of individual common variants. Thirdly, only two variants in the KIF1B gene were assessed in this study, which may fail to reflect the genetic mechanism of other KIF1B variants in the development of HCC.
In conclusion, we identified a statistically significant interaction between the rs17401966 variant of KIF1B and alcohol consumption that contributes to the development of HCC in the Shunde region of China. This study further supports the hypothesis that KIF1B is an important susceptibility gene for HCC in the Chinese population. Comprehensive studies with larger sample sizes and more diverse independent populations are warranted to better understand the underlying mechanisms of KIF1B genetic variants in the development of HCC.
COMMENTS
Background
Several environmental factors have been identified that increase the risk of hepatocellular carcinoma (HCC). However, only a small percentage of individuals who are exposed to these risk factors will eventually develop HCC, highlighting genetic susceptibility as another factor at play in the development of HCC. HCC involves a complex interplay of multiple genetic and environmental factors.
Research frontiers
According to a recent genome-wide association study, KIF1B has been identified as a promising susceptibility gene for HCC in Chinese adults. However, one of the significant variants (rs17401966) in this study yielded inconsistent results in the subsequent replication studies. Indeed, it is important to evaluate the role of rs17401966 in genetic susceptibility to HCC and gene-environment interactions.
Innovations and breakthroughs
The authors confirm the gene-environment interaction between the KIF1B rs17401966 variant and alcohol consumption in the development of HCC in Chinese individuals.
Applications
KIF1B SNPs and gene-environment interaction should be added as valuable knowledge in the field of hepatology.
Peer-review
The authors conducted a case-control study with HCC patients and hospital-based controls to clarify the effect of rs17401966 in KIF1B on HCC and further examined the potential interaction between variants in KIF1B and environmental factors on the risk of HCC in a high-risk region of China. They found a gene-environment interaction between the KIF1B rs17401966 variant and alcohol consumption influenced the development of HCC in Chinese individuals. Their findings add valuable knowledge in the field of hepatology.
Footnotes
P- Reviewer: Cerwenka HR, Iwasaki Y, Qadri I, Sergi C S- Editor: Gong ZM L- Editor: Filipodia E- Editor: Zhang DN
Barbara L, Benzi G, Gaiani S, Fusconi F, Zironi G, Siringo S, Rigamonti A, Barbara C, Grigioni W, Mazziotti A. Natural history of small untreated hepatocellular carcinoma in cirrhosis: a multivariate analysis of prognostic factors of tumor growth rate and patient survival.Hepatology. 1992;16:132-137.
[PubMed] [DOI][Cited in This Article: ][Cited by in Crossref: 311][Cited by in F6Publishing: 322][Article Influence: 10.1][Reference Citation Analysis (0)]
Ebara M, Ohto M, Shinagawa T, Sugiura N, Kimura K, Matsutani S, Morita M, Saisho H, Tsuchiya Y, Okuda K. Natural history of minute hepatocellular carcinoma smaller than three centimeters complicating cirrhosis. A study in 22 patients.Gastroenterology. 1986;90:289-298.
[PubMed] [DOI][Cited in This Article: ]
Munirajan AK, Ando K, Mukai A, Takahashi M, Suenaga Y, Ohira M, Koda T, Hirota T, Ozaki T, Nakagawara A. KIF1Bbeta functions as a haploinsufficient tumor suppressor gene mapped to chromosome 1p36.2 by inducing apoptotic cell death.J Biol Chem. 2008;283:24426-24434.
[PubMed] [DOI][Cited in This Article: ][Cited by in Crossref: 76][Cited by in F6Publishing: 80][Article Influence: 5.0][Reference Citation Analysis (0)]
Zheng X, Wang L, Zhu Y, Guan Q, Li H, Xiong Z, Deng L, Lu J, Miao X, Cheng L. The SNP rs961253 in 20p12.3 is associated with colorectal cancer risk: a case-control study and a meta-analysis of the published literature.PLoS One. 2012;7:e34625.
[PubMed] [DOI][Cited in This Article: ][Cited by in Crossref: 11][Cited by in F6Publishing: 13][Article Influence: 1.1][Reference Citation Analysis (0)]
Xie X, Ma H, Lu Y, Fand Y, Ye X, Wu T, Dong S, Chen W, Cheng J. The seroepidemiological study on hepatitis C virus infection among general population in Shenzhen City (in Chinese).Jibing Kongzhi Zazhi. 2012;17:604-607.
[PubMed] [DOI][Cited in This Article: ]
Rong X, Xia W, Wang M, Wang Y, Zheng Y, Ye X, Luo G, Wang C, Bei C, Fu Y. Seroepidemiological studies of HCV among first-time volunteer blood donors in Guangzhou,China (in Chinese).Zhongguo Shuxue Zazhi. 2009;22:883-885.
[PubMed] [DOI][Cited in This Article: ]
Schlisio S, Kenchappa RS, Vredeveld LC, George RE, Stewart R, Greulich H, Shahriari K, Nguyen NV, Pigny P, Dahia PL. The kinesin KIF1Bbeta acts downstream from EglN3 to induce apoptosis and is a potential 1p36 tumor suppressor.Genes Dev. 2008;22:884-893.
[PubMed] [DOI][Cited in This Article: ][Cited by in Crossref: 248][Cited by in F6Publishing: 252][Article Influence: 15.8][Reference Citation Analysis (0)]
Tan Y, Jiang Q, Dun Z, Wang P, Chen Z, Ji G, Tan Y, Huang R, Xu Y, Xu X. Status and associated factors of alcohol consumption among residents aged 15 and above in Guang-dong Province (in Chinese).Huanan Yufang Yixue. 2015;31:213-217.
[PubMed] [DOI][Cited in This Article: ]
Varela-Rey M, Woodhoo A, Martinez-Chantar ML, Mato JM, Lu SC. Alcohol, DNA methylation, and cancer.Alcohol Res. 2013;35:25-35.
[PubMed] [DOI][Cited in This Article: ]
Chiesa R, Donato F, Tagger A, Favret M, Ribero ML, Nardi G, Gelatti U, Bucella E, Tomasi E, Portolani N. Etiology of hepatocellular carcinoma in Italian patients with and without cirrhosis.Cancer Epidemiol Biomarkers Prev. 2000;9:213-216.
[PubMed] [DOI][Cited in This Article: ]
