Infectious Agents

Metabolic syndrome and hepatocellular carcinoma risk

BACKGROUND

Hepatocellular carcinoma (HCC) has been associated to diabetes and obesity, but a possible association with the metabolic syndrome (MetS) and its potential interaction with hepatitis is open to discussion.

METHODS

We analysed data from an Italian case-control study, including 185 HCC cases and 404 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed from unconditional logistic regression models.

RESULTS

Among the MetS components, diabetes and obesity (i.e, body mass index (BMI)≥30 kg m(-2)) were positively associated to HCC risk, with ORs of 4.33 (95% CI, 1.89-9.86) and 1.97 (95% CI, 1.03-3.79), respectively. The ORs for the MetS were 4.06 (95% CI, 1.33-12.38) defining obesity as BMI≥25, and 1.92 (95% CI, 0.38-9.76) defining it as BMI≥30. The risk increased with the number of MetS components, up to an almost four-fold excess risk among subjects with ≥2 MetS factors. Among subjects without chronic infection with hepatitis B and/or C, the OR for those with ≥2 MetS components was over six-fold elevated. There was no consistent association in subjects with serological evidence of hepatitis B and/or C infection.

CONCLUSION

This study found that the risk of HCC increases with the number of MetS components in subjects not chronically infected with hepatitis viruses.

Descriptive epidemiology of gastric adenocarcinoma in the state of Texas by ethnicity: Hispanic versus White non-Hispanic

BACKGROUND

We aimed to evaluate the clinicopathological and demographic characteristics of gastric adenocarcinoma in Hispanics and compare these trends with those found in non-Hispanic Whites in Texas.

METHODS

Records of patients with gastric adenocarcinoma found in the Texas Cancer Registry from 1995 to 2006 were reviewed. Four ethnic-geographic groups were formed: Hispanics residing in El Paso County (a county on the Texas-Mexico border), White non-Hispanics in El Paso County, Hispanics from the remaining counties of Texas combined, and White non-Hispanics from the remaining counties of Texas combined. Adjusted prevalence ratios (PRs) for the outcome of late stage at diagnosis were calculated.

RESULTS

Of 9949 patients, 561 patients were El Paso County residents, of whom 83% were Hispanics. Among the four ethnic-geographic groups, the age-adjusted incidence was the highest in Hispanics in El Paso County (15.5 cases/100000). Tumor pathobiology varied by ethnicity. White non-Hispanics were more likely than Hispanics to have a proximal tumor and less likely to have a poorly differentiated or undifferentiated tumor. In El Paso County, patients in each of the eight age groups under 75 years compared to patients aged ≥85 years were significantly more likely to be at late stage (adjusted PRs 1.44-1.71).

CONCLUSION

The incidence of gastric adenocarcinoma is higher in Hispanics than in Whites in both El Paso County and the remaining portion of Texas. Hispanics have a higher grade of gastric adenocarcinoma. The prevalence of late stage at the time of diagnosis is higher in younger patients than in older patients.

Family history of liver cancer and hepatocellular carcinoma

Familial clustering of hepatocellular carcinoma (HCC) has been frequently reported in eastern Asiatic countries, where hepatitis B infection is common. Little is known about the relationship between family history of liver cancer and HCC in Western populations. We carried out a case-control study in Italy, involving 229 HCC cases and 431 hospital controls. Data on family history were summarized through a binary indicator (yes/no) and a family history score (FHscore), considering selected family characteristics. Odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were obtained from unconditional multiple logistic regression models, including terms for age, sex, study center, education, tobacco smoking, alcohol drinking, hepatitis B surface antigen, and/or anti-hepatitis C virus positivity. We also performed a meta-analysis on family history of liver cancer and liver cancer updated to April 2011 using random-effects models. After adjustment for chronic infection with hepatitis B/C viruses, family history of liver cancer was associated with HCC risk, when using both the binary indicator (OR, 2.38; 95% CI, 1.01-5.58) and the FHscore, with increasing ORs for successive score categories. Compared to subjects without family history and no chronic infection with hepatitis B/C viruses, the OR for those exposed to both risk factors was 72.48 (95% CI, 21.92-239.73). In the meta-analysis, based on nine case-control and four cohort studies, for a total of approximately 3,600 liver cancer cases, the pooled relative risk for family history of liver cancer was 2.50 (95% CI, 2.06-3.03).

CONCLUSION

A family history of liver cancer increases HCC risk, independently of hepatitis. The combination of family history of liver cancer and hepatitis B/C serum markers is associated with an over 70-fold elevated HCC risk.

Male circumcision and human papillomavirus infection in men: a systematic review and meta-analysis

BACKGROUND

We systematically reviewed the evidence for an association between male circumcision and Human Papillomavirus (HPV) infection and genital warts in men.

METHODS

PubMed and Embase were searched to 15 September 2010. The measure of effect was the adjusted odds ratio (OR) or rate ratio (RR) when present and the crude estimate otherwise. Random effects meta-analyses were used to calculate summary measures of effect.

RESULTS

We identified 23 papers about the association between circumcision and HPV DNA. Circumcised men were less likely to have prevalent genital HPV infection than uncircumcised men (summary OR, 0.57, 95% confidence interval [CI], 0.45-0.71) with between-study heterogeneity (P-heterogeneity = 0.006; I(2) = 50.5%; 19 studies). Similar summary associations were seen in clinical and methodological subgroups. The effect of circumcision was stronger at the glans/corona (OR, 0.47; 95% CI, 0.37-0.60) and urethra (OR, 0.35; 95% CI, 0.12-1.05) compared with sites more distal to the foreskin. There was weak evidence that circumcision was associated with decreased HPV incidence (summary RR, 0.75, 95% CI, 0.57-0.99; 3 studies) and increased HPV clearance (summary RR, 1.33; 95% CI, 0.89-1.98; 3 studies) but no evidence of an association with prevalent genital warts (OR, 0.93, 95% CI, 0.65-1.33; 15 studies).

CONCLUSIONS

Several countries are expanding access to voluntary medical male circumcision to reduce HIV prevalence. This could provide additional benefit in reducing HPV prevalence.

Sexually transmitted infections and prostate cancer among men in the U.S. military

Studies of self-reported sexually transmitted infections (STI) suggesting an association with prostate cancer may reflect underreporting of such infections among nondiseased subjects. To reduce such bias, we studied archived sera in a cohort of U.S. military personnel known to have high rates of both STIs and prostate cancer. Using a nested case-control design, serum samples from 534 men who served on active duty between September 1, 1993 and September 1, 2003 were examined. Controls were individually matched to cases based on date of serum collection, date of birth, branch of service, military rank, marital status, and race. Each of the 267 case-control pairs had two serum samples: a recent serum sample, taken approximately 1 year before the case's prostate cancer diagnosis, and an earlier serum sample, taken approximately 8 years before diagnosis. Each serum specimen was studied for antibodies against human papillomavirus, herpes simplex virus-2 (HSV-2), and Chlamydia trachomatis. Logistic regression accounted for matching and potential confounding factors. Study data indicated no association between prostate cancer and serologic evidence of infections just before the reference date. However, a statistically significant association between prostate cancer and serologic evidence of HSV-2 infection was detected in the earlier sample (odds ratio, 1.60; 95% confidence interval, 1.05-2.44). The strength of this association increased when analyses were restricted to sera collected at least 60 months before diagnosis (odds ratio, 2.04; 95% confidence interval, 1.26-3.29; 204 pairs). If this association is causal, then our findings would suggest a long latency period for prostate cancer development after HSV-2 infection.

Population differences in immune marker profiles associated with human T-lymphotropic virus type I infection in Japan and Jamaica

The natural history of human T-lymphotropic virus type I (HTLV-I) has been shown to differ markedly by geographic area. The differences include contrasting patterns of risk of adult T-cell lymphoma (ATL) and HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), which may be due in part to differences in host immune response to infection. To characterize variations in host immunity across populations, we compared serologic immune marker patterns in HTLV-I-endemic populations in Japan and Jamaica. We matched 204 participants with archived blood from the Miyazaki Cohort Study (Japan) and the Food Handlers Study (Jamaica)-i.e., 51 HTLV-I-positive ("carriers") and 51 HTLV-I-negative individuals ("noncarriers") from each population-by age, sex and blood collection year. We compared plasma concentrations of markers of T-cell-mediated (antigen-specific) and nonspecific immunity using regression models and correlation coefficients. Compared to Jamaican HTLV-I noncarriers, Japanese noncarriers had higher covariate-adjusted mean levels of T-cell activation markers, including antibody to Epstein-Barr virus nuclear antigen-1 (reciprocal titer 27 vs. 71, respectively, p=0.005), soluble interleukin-2 receptor-alpha (477 vs. 623 pg/mL, p=0.0008) and soluble CD30 (34 vs. 46 U/mL, p=0.0001) and lower levels of C-reactive protein (1.1 vs. 0.43 microg/mL, p=0.0004). HTLV-I infection was associated with activated T-cell immunity in Jamaicans but with diminished T-cell immunity in Japanese persons. The observed population differences in background and HTLV-I-related host immunity correspond closely to the divergent natural histories of infection observed among HTLV-I carriers in Japan and Jamaica and corroborate a role for host immune status in the contrasting patterns of ATL and HAM/TSP risk.

Epstein-Barr virus associated gastric carcinoma: epidemiological and clinicopathological features

In this paper, the roles of Epstein-Barr virus (EBV) in gastric carcinogenesis are discussed, reviewing mainly epidemiological and clinicopathological studies. About 10% of gastric carcinomas harbor clonal EBV. LMP1, an important EBV oncoprotein, is only rarely expressed in EBV-associated gastric carcinoma (EBV-GC) while EBV-encoded small RNA is expressed in almost every EBV-GC cell, suggesting its importance for developing and maintaining this carcinoma. In addition, the hypermethylation-driven suppressor gene downregulation, frequently observed in EBV-GC, appears to give a selective advantage for carcinoma cells. EBV reactivation is suspected to precede EBV-GC development since antibodies against EBV-related antigens, including EBV capsid antigen (VCA), are elevated in prediagnostic sera. Interestingly, the average anti-VCA immunoglobulin G antibody titer in EBV-GC patients was significantly higher among men than among women, whereas EBV-negative GC cases did not show such a sex difference. A higher frequency of human leucocyte antigen-DR11 in EBV-GCs suggests that major histocompatibility complex-restricted EBV nuclear antigen 1 epitope recognition may enhance EBV reactivation. EBV infection of gastric cells by lymphocytes with reactivated EBV is suspected to be the first step of EBV-GC development. Male predominance of EBV-GC suggests the involvement of lifestyles and occupational factors common among men. The predominance of EBV with XhoI+ and BamHI type i polymorphisms in EBV-GC in Latin America suggests a possibility of some EBV oncogene expressions being affected by EBV polymorphism. The lack of such predominance in Asian countries, however, indicates an interaction between EBV polymorphism and the host response. In conclusion, further studies are necessary to examine the interaction between EBV infection, its polymorphisms, environmental factors, and genetic backgrounds.