Risk of hepatocellular carcinoma in people with HIV in the United States, 2001-2019.

BACKGROUND: People with HIV have higher risk of hepatocellular carcinoma than the general population, partly because of higher prevalence of coinfection with hepatitis B virus (HBV) or hepatitis C virus (HCV). METHODS: We calculated standardized incidence ratios for hepatocellular carcinoma in people with HIV by comparing rates from people with HIV in the HIV/AIDS Cancer Match Study, a population-based HIV and cancer registry linkage, to those in the general population. We used multivariable Poisson regression to estimate adjusted incidence rate ratios among people with HIV and linked the Texas HIV registry with medical claims data to estimate adjusted odds ratios (AORs) of HBV and HCV in hepatocellular carcinoma patients with logistic regression. RESULTS: Compared with the general population, hepatocellular carcinoma rates in people with HIV were elevated 2.79-fold (n = 1736; 95% confidence interval [CI] = 2.66 to 2.92). Hepatocellular carcinoma rates decreased statistically significantly from 2001-2004 to 2015-2019 (P < .001). Compared with men who have sex with men, hepatocellular carcinoma risk was elevated 4.28-fold among men who injected drugs (95% CI = 3.72 to 4.93) and 1.83-fold among women who injected drugs (95% CI = 1.49 to 2.26). In Texas, 146 hepatocellular carcinoma cases among people with HIV were linked to claims data: 25% HBV positive, 59% HCV positive, and 13% coinfected with HBV and HCV. Compared with men who had sex with men, people who inject drugs had 82% decreased odds of HBV (AOR = 0.18, 95% CI = 0.05 to 0.63) and 2 times the odds of HCV (AOR = 20.4, 95% CI = 3.32 to 125.3). CONCLUSIONS: During 2001-2019, hepatocellular carcinoma risk declined among people with HIV, though rates remain statistically significantly elevated compared with the general population, particularly among people who inject drugs. Prevention and treatment of HBV/HCV are needed to reduce hepatocellular carcinoma risk among people with HIV.

Cancers Attributable to Infections in the US in 2017: A Meta-Analysis.

Importance: Infections are largely modifiable causes of cancer. However, there remains untapped potential for preventing and treating carcinogenic infections in the US. Objective: To estimate the percentage and number of incident cancers attributable to infections in the US among adults and children for the most recent year cancer incidence data were available (2017). Data Sources: A literature search from 1946 onward was performed in MEDLINE on January 6, 2023, to obtain the data required to calculate population attributable fractions for 31 infection-cancer pairs. National Health and Nutrition Examination Survey data were used to estimate the population prevalence of hepatitis B and C viruses and Helicobacter pylori. Study Selection: Studies conducted in the US or other Western countries were selected according to specific infection-cancer criteria. Data Extraction and Synthesis: Data from 128 studies were meta-analyzed to obtain the magnitude of an infection-cancer association or prevalence of the infection within cancer cells. Main Outcomes and Measures: The proportion of cancer incidence attributable to 8 infections. Results: Of the 1 666 102 cancers diagnosed in 2017 among individuals aged 20 years or older in the US, 71 485 (4.3%; 95% CI, 3.1%-5.3%) were attributable to infections. Human papillomavirus (n = 38 230) was responsible for the most cancers, followed by H pylori (n = 10 624), hepatitis C virus (n = 9006), Epstein-Barr virus (n = 7581), hepatitis B virus (n = 2310), Merkel cell polyomavirus (n = 2000), Kaposi sarcoma-associated herpesvirus (n = 1075), and human T-cell lymphotropic virus type 1 (n = 659). Cancers with the most infection-attributable cases were cervical (human papillomavirus; n = 12 829), gastric (H pylori and Epstein-Barr virus; n = 12 565), oropharynx (human papillomavirus; n = 12 430), and hepatocellular carcinoma (hepatitis B and C viruses; n = 10 017). The burden of infection-attributable cancers as a proportion of total cancer incidence ranged from 9.6% (95% CI, 9.2%-10.0%) for women aged 20 to 34 years to 3.2% (95% CI, 2.4%-3.8%) for women aged 65 years or older and from 6.1% (95% CI, 5.2%-7.0%) for men aged 20 to 34 years to 3.3% (95% CI, 1.9%-4.4%) for men aged 65 years or older. Among those aged 19 years or younger, 2.2% (95% CI, 1.3%-3.0%) of cancers diagnosed in 2017 were attributable to Epstein-Barr virus. Conclusions and Relevance: Infections were estimated to be responsible for 4.3% of cancers diagnosed among adults in the US in 2017 and, therefore, represent an important target for cancer prevention efforts.

Decreasing incidence of hepatocellular carcinoma among most racial groups: SEER-22, 2000-2019.

BACKGROUND: Hepatocellular carcinoma (HCC) incidence was rising in the United States. Previously, using data collected by the Surveillance, Epidemiology, and End Results (SEER) Program through 2017, we found that overall incidence had begun to decline, although not in Black and American Indian/Alaska Native (AI/AN) populations. Utilizing expanded SEER data encompassing ~50% of the population, we examined secular trends and demographic differences in HCC incidence through 2019. METHODS: We included cases of HCC diagnosed in adults aged ≥20 years residing in SEER-22 registry areas. We examined case counts, incidence rates (per 100,000 person-years), annual percent changes (APCs), and calendar years when APCs changed significantly. RESULTS: HCC incidence increased from 5.56 in 2000 to 8.89 in 2009 (APC, 5.17%), then rose more slowly during 2009-2015 (APC, 2.28%). After peaking at 10.03 in 2015, incidence fell to 9.20 in 2019 (APC, -2.26%). In Asian/Pacific Islanders (A/PI), the decline began in 2007 and accelerated in 2015 (APCs: 2007-2015, -1.84%; 2015-2019, -5.80%). In 2014, incidence began to fall in the White (APC: 2014-2019, -1.11%) and Hispanic populations (APC: 2014-2019, -1.72%). In 2016, rates began to fall in Black individuals (APC: 2016-2019, -6.05%). In the AI/AN population, incidence was highest in 2017, although the subsequent decline was not statistically significant. In 2019, population-specific rates were: White, 6.94; Black, 10.74; A/PI, 12.11; AI/AN, 14.56; Hispanic, 15.48. CONCLUSION: HCC incidence is now decreasing in most US racial/ethnic populations, including among Black individuals. The onset of decline differed among racial/ethnic groups and wide disparities in HCC rates remain.

IFNL4 Genotype Frequencies in Asian Populations Support Shorter Duration Therapy with Sofosbuvir-Based Hepatitis C Virus Regimens to Increase the Number Cured.

Globally, ∼56.8 million people are chronically infected with hepatitis C virus (HCV), with about half residing in Asia. The cost and efficiency of delivering regimens based on direct-acting antiviral agents for HCV are important considerations in implementing these curative treatments. For sofosbuvir-based regimens, most patients are treated for 12 weeks; however, treatment for 8 weeks has been shown to cure HCV infection in 95% of patients without cirrhosis. Furthermore, virological failure after 8-week treatment occurs in only 1%-2% of individuals without cirrhosis, who have a favorable IFNL4 genotype, which is present in >50% of South Asians and >80% of East Asians. We propose that sofosbuvir-based treatment for 8 weeks, or perhaps shorter, would yield high response rate regimens in Asian countries and markedly increase the number of patients who could be cured for a given cost of the medication. We propose that a noninferiority trial in an East Asian population be conducted to test this hypothesis.

Hepatitis B virus and hepatitis D virus infection in women with or at risk for HIV infection in the United States.

Hepatitis D virus (HDV) requires co-infection with hepatitis B virus (HBV). Human immunodeficiency virus (HIV) shares transmission routes with these viruses. Among 4,932 US women infected with or at-risk for HIV during 1994-2015, HBV surface antigen (HBsAg) positivity was more common in women with HIV (2.8% vs. 1.2%; p = 0.001); HDV was more common among participants enrolled during 2013-2015 (p = 0.0004) and those with resolved rather than active hepatitis C (1.9% vs. 0.5%; p = 0.02). Among HBsAg-positive women (n = 117), HDV antibody prevalence was 22% and did not vary by HIV status; HDV infection was associated with the presence of advanced fibrosis/cirrhosis at enrollment (adjusted odds ratio, 5.70; 95% confidence interval, 1.46-22.29). Our results demonstrate the importance of HDV testing in HBV-infected US women.

No Association of IFNL4 Genotype With Opportunistic Infections and Cancers Among Men With Human Immunodeficiency Virus 1 Infection.

BACKGROUND: IFNL4 genetic variants that are strongly associated with clearance of hepatitis C virus have been linked to risk of certain opportunistic infections (OIs) and cancers, including Kaposi sarcoma, cytomegalovirus infection, and herpes simplex virus infection. As the interferon (IFN) λ family plays a role in response to viral, bacterial, and fungal infections, IFNL4 genotype might affect risk for a wide range of OIs/cancers. METHODS: We examined associations between genotype for the functional IFNL4 rs368234815 polymorphism and incidence of 16 OIs/cancers among 2310 men with human immunodeficiency virus (2038 white; 272 black) enrolled in the Multicenter AIDS Cohort Study during 1984-1990. Our primary analyses used Cox proportional hazards models adjusted for self-reported racial ancestry to estimate hazard ratios with 95% confidence intervals, comparing participants with the genotypes that generate IFN-λ4 and those with the genotype that abrogates IFN-λ4. We censored follow-up at the introduction of highly effective antiretroviral therapies. RESULTS: We found no statistically significant association between IFNL4 genotype and the incidence of Kaposi sarcoma (hazard ratio, 0.92 [95% confidence interval, .76-1.11]), cytomegalovirus infection (0.94 [.71-1.24]), herpes simplex virus infection (1.37 [.68-2.93]), or any other OI/cancer. We observed consistent results using additive genetic models and after controlling for CD4 cell count through time-dependent adjustment or restriction to participants with a low CD4 cell count. CONCLUSIONS: The absence of associations between IFNL4 genotype and these OIs/cancers provides evidence that this gene does not affect the risk of disease from opportunistic pathogens.

Association between Immunologic Markers and Cirrhosis in Individuals from a Prospective Chronic Hepatitis C Cohort.

Background: Chronic hepatitis C virus (HCV) infection can affect immune response and inflammatory pathways, leading to severe liver diseases such as cirrhosis and hepatocellular carcinoma (HCC). Methods: In a prospective cohort of chronically HCV-infected individuals, we sampled 68 individuals who developed cirrhosis, 91 controls who did not develop cirrhosis, and 94 individuals who developed HCC. Unconditional odds ratios (ORs) from polytomous logistic regression models and canonical discriminant analyses (CDAs) were used to compare categorical (C) baseline plasma levels for 102 markers in individuals who developed cirrhosis vs. controls and those who developed HCC vs. cirrhosis. Leave-one-out cross validation was used to produce receiver operating characteristic curves to assess predictive ability of markers. Lastly, biological pathways were assessed in association with cirrhotic development compared to controls. Results: After multivariable adjustment, DEFA-1 (OR: C2v.C1 = 7.73; p < 0.0001), ITGAM (OR: C2v.C1 = 4.03; p = 0.0002), SCF (OR: C4v.C1 = 0.19; p-trend = 0.0001), and CCL11 (OR: C4v.C1 = 0.31; p-trend= 0.002) were all associated with development of cirrhosis compared to controls; these markers, together with clinical/demographics variables, improved prediction of cirrhosis from 55.7% (in clinical/demographic-only model) to 74.9% accuracy. A twelve-marker model based on CDA results further increased prediction of cirrhosis to 88.0%. While six biological pathways were found to be associated with cirrhosis, cell adhesion was the only pathway associated with cirrhosis after Bonferroni correction. In contrast to cirrhosis, DEFA-1 and ITGAM levels were inversely associated with HCC risk. Conclusions: Pending validation, these findings highlight the important role of immunological markers in predicting HCV-related cirrhosis even 11 years post-enrollment.

The role of IFNL4 in liver inflammation and progression of fibrosis.

The discovery that genetic variation within the interferon lambda locus has a profound effect on the outcome of hepatitis C virus (HCV) treatment and spontaneous clearance of HCV is one of the great triumphs of genomic medicine. Subsequently, the IFNL4 gene was discovered and proposed as the causal gene underlying this association. However, there has been a lively debate within the field concerning the causality, which has been further complicated by a change in naming. This review summarizes the genetic data available for the IFNL3/IFNl4 loci and provides an in-depth discussion of causality. We also discuss a new series of interesting data suggesting that the genetic variation at the IFNL4 loci influences the evolution of the HCV virus and the implication this relationship between our genetic makeup and virus evolution has upon our understanding of the IFNL4 system. Finally, new data support an influence of the IFNL4 gene upon liver inflammation and fibrosis that is independent of etiology, thereby linking the IFNL4 gene to some of the major liver diseases of today.

Declining US Hepatocellular Carcinoma Rates, 2014-2017.

Liver cancer is a prominent cause of cancer death in the United States.1 Rates of hepatocellular carcinoma (HCC), the most common histologic subtype,2 increased for decades,3 until recent years when rates flattened,4 and then potentially declined. Previously, we reported that US HCC rates in 2016 were 4% lower than 20155; however, it was unclear from those data whether that finding reflected a true downward trend. Here, we examine HCC rates through 2017.

The Impact of IFNλ4 on the Adaptive Immune Response to SARS-CoV-2 Infection.

Genetic polymorphisms at the IFNL4 loci are known to influence the clinical outcome of several different infectious diseases. Best described is the association between the IFNL4 genotype and hepatitis C virus clearance. However, an influence of the IFNL4 genotype on the adaptive immune system was suggested by several studies but never investigated in humans. In this cross-sectional study, we have genotyped 201 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-positive participants for 3 IFNL4 polymorphisms (rs368234815, rs12979860, and rs117648444) and stratified them according to the IFNλ4 activity. Based on this stratification, we investigated the association between the IFNL4 genotype and the antibody as well as the CD8+ T cell response in the acute phase of the SARS-CoV-2 infection. We observed no differences in the genotype distribution compared with a Danish reference cohort or the 1,000 Genome Project, and we were not able to link the IFNL4 genotype to changes in either the antibody or CD8+ T cell responses of these patients.

Association between immunologic markers and cirrhosis in individuals with chronic hepatitis B.

Host immune response and chronic inflammation associated with chronic hepatitis B virus (HBV) infection play a key role in the pathogenesis of liver diseases such as cirrhosis and hepatocellular carcinoma (HCC). We sampled 175 HCC, 117 cirrhotic and 165 non-cirrhotic controls from a prospective cohort study of chronically HBV-infected individuals. Multivariable polytomous logistic regression and canonical discriminant analysis (CDA) were used to compare baseline plasma levels for 102 markers in individuals who developed cirrhosis vs. controls and those who developed HCC vs. cirrhosis. Leave-one-out cross validation was used to generate receiver operating characteristic curves to compare the predictive ability of marker groups. After multivariable adjustment, HGF (Q4v1OR: 3.74; p-trend = 0.0001), SLAMF1 (Q4v1OR: 4.07; p-trend = 0.0001), CSF1 (Q4v1OR: 3.00; p-trend = 0.002), uPA (Q4v1OR: 3.36; p-trend = 0.002), IL-8 (Q4v1OR: 2.83; p-trend = 0.004), and OPG (Q4v1OR: 2.44; p-trend = 0.005) were all found to be associated with cirrhosis development compared to controls; these markers predicted cirrhosis with 69% accuracy. CDA analysis identified a nine marker model capable of predicting cirrhosis development with 79% accuracy. No markers were significantly different between HCC and cirrhotic participants. In this study, we assessed immunologic markers in relation to liver disease in chronically-HBV infected individuals. While validation in required, these findings highlight the importance of immunologic processes in HBV-related cirrhosis.

Intracellular Accumulation of IFN-λ4 Induces ER Stress and Results in Anti-Cirrhotic but Pro-HCV Effects.

IFNL3/IFNL4 polymorphisms are inversely associated with the risk of chronic hepatitis C virus (HCV) infection and cirrhosis, two major risk factors for developing hepatocellular carcinoma (HCC). To further explore these inverse associations and their molecular underpinnings, we analyzed IFNL3/IFNL4 polymorphisms represented by the IFNL4 genotype (presence of rs368234815-dG or rs12979860-T alleles) in HCV patients: 2969 from Japan and 2931 from Taiwan. IFNL4 genotype was associated with an increased risk of HCV-related HCC (OR=1.28, 95%CI=1.07-1.52, P=0.0058) in the general population of Japanese patients, but not in Taiwanese patients who achieved treatment-induced viral clearance. IFNL4 genotype was also associated with a decreased risk of cirrhosis (OR=0.66, 95%CI=0.46-0.93, P=0.018, in Taiwanese patients). We then engineered HepG2 cells to inducibly express IFN-λ4 in the presence or absence of interferon lambda receptor 1 (IFNLR1). Induction of IFN-λ4 resulted in its intracellular accumulation, mainly in lysosomes and late endosomes, and increased ER stress, leading to apoptosis and reduced proliferation. We identified the very-low-density lipoprotein receptor (VLDLR), which facilitates HCV entry into hepatocytes, as a transcript induced by IFN-λ4 but not IFN-λ3. Our results suggest that the molecular mechanisms underlying the anti-cirrhotic but pro-HCV associations observed for IFNL3/IFNL4 polymorphisms are, at least in part, contributed by intracellular accumulation of IFN-λ4 causing ER stress in hepatic cells.

Immunologic markers and risk of hepatocellular carcinoma in hepatitis B virus- and hepatitis C virus-infected individuals.

BACKGROUND: Clinical and experimental studies suggest immunologic proteins contribute to hepatocellular carcinoma (HCC) development. AIM: To evaluate circulating immunologic markers and HCC risk. METHODS: From a Taiwanese cohort of chronically hepatitis B virus (HBV)-infected individuals followed over time (REVEAL-HBV), we sampled 175 who developed HCC, 117 cirrhosis only, and 165 non-cirrhotic controls. From a similar Taiwanese cohort of chronically hepatitis C virus (HCV)-infected individuals (REVEAL-HCV), we included 94 individuals who developed HCC, 68 cirrhosis only and 100 non-cirrhotic controls. We compared pre-diagnostic plasma levels of 102 markers in HCC cases to non-cirrhotic and cirrhotic controls using polytomous logistic regression. A priori markers included insulin-like growth factor binding protein-3 (IGFBP-3), intercellular adhesion molecule 1 (ICAM-1) and interleukin 6 (IL-6). P-values for other markers were corrected for multiple testing (false discovery rate = 10%). RESULTS: In both REVEAL-HBV and REVEAL-HCV, increasing levels of ICAM-1 were associated with increased risk of HCC compared to non-cirrhotic controls (P-trend 0.02 and 0.001, respectively). In both REVEAL-HBV and REVEAL-HCV, two novel markers [C-X-C motif chemokine 11 (CXCL11) and hepatocyte growth factor (HGF)] were positively associated [strongest odds ratioquartile 4 versus 1 (OR) 4.55 for HGF in HCV], while two [complement factor H related 5 (CFHR5) and stem cell factor (SCF)] were negatively associated (strongest ORQ4vQ1 0.14 for SCF in HCV) with development of HCC compared to non-cirrhotic controls. CONCLUSIONS: We confirmed the association for ICAM-1 and identified 4 additional proteins associated with HBV- and HCV-related HCC. These findings highlight the importance of immunologic processes in HBV- and HCV-related HCC.

Death certificates compared to SEER-Medicare data for surveillance of liver cancer mortality due to hepatitis B or hepatitis C infection.

Hepatocellular carcinoma (HCC) is often caused by hepatitis B virus (HBV) or hepatitis C virus (HCV) infection. To investigate the completeness of death certificates for recording viral hepatitis in HCC death, we compared the proportion of HCC deaths with hepatitis virus infection reported on death certificates to that reported as claims in the Surveillance, Epidemiology, and End Results (SEER)-Medicare database among individuals ≥66 years of age. For 2001-2015, we tabulated proportions of HCC deaths with HBV or HCV infection in each database overall, and by demographic factors. To correct for under ascertainment of viral hepatitis-associated HCC on death certificates, we multiplied by the reciprocal ratio of death certificates to SEER-Medicare. Among HCC decedents, HBV infection was reported on 3.6% of death certificates and 17.2% of Medicare claims. For HCV, corresponding proportions were 14.9% and 26.9%. The ratio of HBV-attributable HCC deaths in death certificates to SEER-Medicare remained ~0.21 over time. The ratio of HCV-attributable HCC deaths decreased 22.1% per year, from 0.70 in 2001 to 0.37 in 2003, and increased 4.1% per year, from 0.47 in 2004 to 0.66 in 2015. Following correction, the 2015 mortality rate from death certificate data increased from 0.2 to 0.9 per 100,000 for HBV-attributable HCC and from 2.3 to 3.5 per 100,000 for HCV-attributable HCC. In conclusion, among older Americans dying from HCC, death certificates captured 21% of HBV and 55% of HCV infections compared to Medicare claims. Our results suggest that death certificates provide incomplete data for viral hepatitis-associated HCC surveillance.

A Multiancestry Sex-Stratified Genome-Wide Association Study of Spontaneous Clearance of Hepatitis C Virus.

BACKGROUND: Spontaneous clearance of acute hepatitis C virus (HCV) infection is more common in women than in men, independent of known risk factors. METHODS: To identify sex-specific genetic loci, we studied 4423 HCV-infected individuals (2903 male, 1520 female) of European, African, and Hispanic ancestry. We performed autosomal, and X chromosome sex-stratified and combined association analyses in each ancestry group. RESULTS: A male-specific region near the adenosine diphosphate-ribosylation factor-like 5B (ARL5B) gene was identified. Individuals with the C allele of rs76398191 were about 30% more likely to have chronic HCV infection than individuals with the T allele (OR, 0.69; P = 1.98 × 10-07), and this was not seen in females. The ARL5B gene encodes an interferon-stimulated gene that inhibits immune response to double-stranded RNA viruses. We also identified suggestive associations near septin 6 and ribosomal protein L39 genes on the X chromosome. In box sexes, allele G of rs12852885 was associated with a 40% increase in HCV clearance compared with the A allele (OR, 1.4; P = 2.46 × 10-06). Septin 6 facilitates HCV replication via interaction with the HCV NS5b protein, and ribosomal protein L39 acts as an HCV core interactor. CONCLUSIONS: These novel gene associations support differential mechanisms of HCV clearance between the sexes and provide biological targets for treatment or vaccine development.

Multi-ancestry fine mapping of interferon lambda and the outcome of acute hepatitis C virus infection.

Clearance of acute infection with hepatitis C virus (HCV) is associated with the chr19q13.13 region containing the rs368234815 (TT/ΔG) polymorphism. We fine-mapped this region to detect possible causal variants that may contribute to HCV clearance. First, we performed sequencing of IFNL1-IFNL4 region in 64 individuals sampled according to rs368234815 genotype: TT/clearance (N = 16) and ΔG/persistent (N = 15) (genotype-outcome concordant) or TT/persistent (N = 19) and ΔG/clearance (N = 14) (discordant). 25 SNPs had a difference in counts of alternative allele >5 between clearance and persistence individuals. Then, we evaluated those markers in an association analysis of HCV clearance conditioning on rs368234815 in two groups of European (692 clearance/1 025 persistence) and African ancestry (320 clearance/1 515 persistence) individuals. 10/25 variants were associated (P < 0.05) in the conditioned analysis leaded by rs4803221 (P value = 4.9 × 10-04) and rs8099917 (P value = 5.5 × 10-04). In the European ancestry group, individuals with the haplotype rs368234815ΔG/rs4803221C were 1.7× more likely to clear than those with the rs368234815ΔG/rs4803221G haplotype (P value = 3.6 × 10-05). For another nearby SNP, the haplotype of rs368234815ΔG/rs8099917T was associated with HCV clearance compared to rs368234815ΔG/rs8099917G (OR: 1.6, P value = 1.8 × 10-04). We identified four possible causal variants: rs368234815, rs12982533, rs10612351 and rs4803221. Our results suggest a main signal of association represented by rs368234815, with contributions from rs4803221, and/or nearby SNPs including rs8099917.

Prediagnostic serum polychlorinated biphenyl concentrations and primary liver cancer: A case-control study nested within two prospective cohorts.

BACKGROUND: Polychlorinated biphenyls (PCBs) were used in electrical equipment and a range of construction materials. Although banned in the United States and most of Europe in the 1970s, they are highly persistent in the environment and bioaccumulate. Whether PCBs are associated with liver cancer risk at general population levels is unknown. METHODS: This study consisted of 136 incident liver cancer cases and 408 matched controls from the Kaiser Permanente Northern California Multiphasic Health Checkup (MHC) cohort and 84 cases and 252 matched controls from the Norwegian Janus cohort. Sera collected in the 1960s-1980s were measured for 37 PCB congeners and markers of hepatitis B (HBV) and C (HCV) infection. Odds ratios (OR) and 95% confidence intervals (CI) for tertiles of each lipid-adjusted PCB were estimated from conditional logistic regression. We also examined the molar sum of congeners in groups: total PCBs; low, medium, and high chlorination; and Wolff functional groups. RESULTS: Concentrations of individual congeners from the 1960s/1970s sera ranged from 1.3-123.0 and 1.4-116.0 ng/g lipid among MHC cases and controls, respectively, and from 1.9-258.0 and 1.9-271.0 ng/g lipid among Janus cases and controls, respectively. Among MHC participants with sera from the 1960s, collected an average of 27 years before diagnosis among cases, the top tertile of PCBs 151, 170, 172, 177, 178, 180, and 195 was significantly associated with elevated odds of liver cancer (OR range = 2.01-2.38); most of these congeners demonstrated exposure-response trends. For example, ORtertile 3vs1 = 2.38 (95% CI: 1.22-4.64, p-trend = 0.01) for PCB 180. As a group, Wolff group 1b congeners, which are biologically persistent and weak phenobarbital inducers, were associated with increased odds. In MHC participants, ever vs. never HBV or HCV infection modified the PCB-liver cancer associations. There was little evidence of an association between PCBs and odds of liver cancer among the Janus cohort. DISCUSSION: We observed associations between a number of PCB congeners and increased odds of liver cancer among MHC, but not Janus, participants with sera from the 1960s/1970s.