A novel causal model for nasopharyngeal carcinoma.

The development of nasopharyngeal carcinoma (NPC) and its unique geographic distribution have long been attributed to a combination of dietary intake of salt-preserved fish, inherited susceptibility, and early-life infection with the Epstein-Barr virus (EBV). New findings from our large, rigorously designed, population-based case-control study of NPC in southern China have enabled substantial revision of this causal model. Here, we briefly summarize these results and provide an updated model of the etiology of NPC. Our new research identifies two EBV genetic variants that may be causally involved in the majority of NPC in southern China, and suggests the rise of modern environmental co-factors accompanying cultural and economic transformation in NPC-endemic regions. These discoveries can be translated directly into clinical and public health advances, including improvement of indoor air quality and oral health, development of an EBV vaccine, enhanced screening strategies, and improved risk prediction. Greater understanding of the roles of environmental, genetic, and viral risk factors can reveal the extent to which these agents act independently or jointly on NPC development. The history of NPC research demonstrates how epidemiology can shed light on the interplay of genes, environment, and infections in carcinogenesis, and how this knowledge can be harnessed for cancer prevention and control.

Cancer risk in the relatives of patients with nasopharyngeal carcinoma­a register-based cohort study in Sweden.

BACKGROUND: Little is known about cancer susceptibility among relatives of nasopharyngeal carcinoma (NPC) patients in non-endemic areas. We conducted a register-based cohort study to assess the relative risks (RRs) of cancer in families of NPC probands in Sweden. METHODS: By linking 11,602,616 Swedish-born individuals (defined as 'general population') identified from national censuses to the Swedish Cancer Register and Multi-Generation Register, we identified 9157 relatives (3645 first-degree and 5512 second-degree) of 1211 NPC probands. Cancer incidence during 1961-2009 was ascertained through the Cancer Register. Relative risks of cancer in the relatives of NPC probands, compared with the rest of the general population, were calculated from Poisson regression models. RESULTS: First-degree relatives had higher risks of NPC (N=2, RR=4.29, 95% confidence interval (CI)=1.07 to 17.17) and cancers of the larynx (N=5, RR=2.53, 95% CI=1.05 to 6.09), prostate (N=76, RR=1.35, 95% CI=1.07 to 1.68), and thyroid (N=10, RR=2.44, 95% CI=1.31 to 4.53) than the rest of the general population. In addition, a raised risk of cancer of the salivary glands was observed among first-degree relatives of probands with undifferentiated NPC (N=2, RR=6.64, 95% CI=1.66 to 26.57). In contrast, a decreased risk of colorectal cancer was observed in first- and second-degree relatives (N=43, RR=0.71, 95% CI=0.53 to 0.96). CONCLUSION: The increased risk of NPC and certain other cancers among first-degree relatives may be explained by shared genetic and environmental risk factors, the latter including Epstein-Barr virus infection and smoking or by increased diagnostic intensity.

Hodgkin lymphoma incidence in California Hispanics: influence of nativity and tumor Epstein-Barr virus.

PURPOSE: For classical Hodgkin lymphoma (HL), migrant studies could elucidate contributions of environmental factors (including Epstein-Barr virus (EBV)) to the lower rates in non-whites. Given the well-described etiologic complexity of HL, this research requires a large, immigrant population, such as California Hispanics. METHODS: With 1988-2004 California Cancer Registry data (2,595 Hispanic, 8,637 white HL cases) and tumor cell EBV status on a subset (218 Hispanics, 656 whites), we calculated ethnicity- and nativity-specific HL incidence rates simultaneously by age, sex, and histologic subtype, and tumor cell EBV prevalence. RESULTS: Compared with white rates, Hispanic HL rates were lower overall (70 %) and for nodular sclerosis HL, particularly among young adults (60-65 % for females). However, they were higher among children (200 %) and older adults, and for mixed cellularity HL. Compared with rates in foreign-born Hispanics, rates in US-born Hispanics were higher among young adults (>threefold in females), lower for children and adults over age 70, and consistently intermediate compared with rates in whites. EBV tumor prevalence was 67, 32, and 23 % among foreign-born Hispanics, US-born Hispanics, and whites, respectively, although with variation by age, sex, and histology. CONCLUSIONS: Findings strongly implicate environmental influences, such as nativity-related sociodemographic differences, on HL occurrence. In addition, lower young adult rates and higher EBV prevalence in US-born Hispanics than in whites raise questions about the duration/extent of environmental change for affecting HL rates and also point to ethnic differences in genetic susceptibility. Lesser variation in mixed cellularity HL rates and greater variation in rates for females across groups suggest less modifiable factors interacting with environmental influences.

Risk of lymphoma subtypes after solid organ transplantation in the United States.

BACKGROUND: Solid organ transplant recipients have high risk of lymphomas, including non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL). A gap in our understanding of post-transplant lymphomas involves the spectrum and associated risks of their many histologic subtypes. METHODS: We linked nationwide data on solid organ transplants from the US Scientific Registry of Transplant Recipients (1987-2008) to 14 state and regional cancer registries, yielding 791 281 person-years of follow-up for 19 distinct NHL subtypes and HL. We calculated standardised incidence ratios (SIRs) and used Poisson regression to compare SIRs by recipient age, transplanted organ, and time since transplantation. RESULTS: The risk varied widely across subtypes, with strong elevations (SIRs 10-100) for hepatosplenic T-cell lymphoma, Burkitt's lymphoma, NK/T-cell lymphoma, diffuse large B-cell lymphoma, and anaplastic large-cell lymphoma (both systemic and primary cutaneous forms). Moderate elevations (SIRs 2-4) were observed for HL and lymphoplasmacytic, peripheral T-cell, and marginal zone lymphomas, but SIRs for indolent lymphoma subtypes were not elevated. Generally, SIRs were highest for younger recipients (<20 years) and those receiving organs other than kidneys. CONCLUSION: Transplant recipients experience markedly elevated risk of a distinct spectrum of lymphoma subtypes. These findings support the aetiologic relevance of immunosuppression for certain subtypes and underscore the importance of detailed haematopathologic workup for transplant recipients with suspected lymphoma.

Cigarette smoking and risk of Hodgkin lymphoma and its subtypes: a pooled analysis from the International Lymphoma Epidemiology Consortium (InterLymph).

BACKGROUND: The etiology of Hodgkin lymphoma (HL) remains incompletely characterized. Studies of the association between smoking and HL have yielded ambiguous results, possibly due to differences between HL subtypes. PATIENTS AND METHODS: Through the InterLymph Consortium, 12 case-control studies regarding cigarette smoking and HL were identified. Pooled analyses on the association between smoking and HL stratified by tumor histology and Epstein-Barr virus (EBV) status were conducted using random effects models adjusted for confounders. Analyses included 3335 HL cases and 14 278 controls. RESULTS: Overall, 54.5% of cases and 57.4% of controls were ever cigarette smokers. Compared with never smokers, ever smokers had an odds ratio (OR) of HL of 1.10 [95% confidence interval (CI) 1.01-1.21]. This increased risk reflected associations with mixed cellularity cHL (OR = 1.60, 95% CI 1.29-1.99) and EBV-positive cHL (OR = 1.81, 95% CI 1.27-2.56) among current smokers, whereas risk of nodular sclerosis (OR = 1.09, 95% CI 0.90-1.32) and EBV-negative HL (OR = 1.02, 95% CI 0.72-1.44) was not increased. CONCLUSION: These results support the notion of etiologic heterogeneity between HL subtypes, highlighting the need for HL stratification in future studies. Even if not relevant to all subtypes, our study emphasizes that cigarette smoking should be added to the few modifiable HL risk factors identified.

A nationwide study of aspirin, other non-steroidal anti-inflammatory drugs, and Hodgkin lymphoma risk in Denmark.

BACKGROUND: We recently found an inverse association between low-dose aspirin use and risk of Hodgkin lymphoma (HL) in northern Denmark. To strengthen the evidence for this association, we expanded the study base to include all of Denmark. METHODS: Between 1997 and 2009, 1659 incident HL cases were identified in nationwide databases and matched with ≤5 population controls on age, sex, and residence. Use of aspirin, selective cyclooxygenase-2 (sCOX-2) inhibitors, and other non-steroidal anti-inflammatory drugs (NSAIDs) from 1995 through 2008 (≥1 year before the index date) was ascertained via the Danish National Prescription Database. Odds ratios (ORs) for associations with HL risk were estimated using conditional logistic regression. RESULTS: Ever use (>2 prescriptions) vs never/rare use (≤2 prescriptions) of low-dose aspirin was not associated with HL risk, but the association with long-term use for ≥7 years vs never/rare use was clearly inverse, although statistically nonsignificantly so (OR=0.65, 95% confidence interval (CI): 0.39-1.09). By contrast, ever use of sCOX-2 inhibitors or other NSAIDs (OR=1.27, 95% CI: 1.10-1.47), especially short-term and low- or medium-intensity use, was associated with elevated HL risk. CONCLUSION: Our results are consistent with the hypothesis that long-term use of low-dose aspirin, but not other NSAIDs, protects against HL development.

Family history of haematopoietic malignancies and non-Hodgkin's lymphoma risk in the California Teachers Study.

Family history of haematopoietic malignancies appears to be a risk factor for non-Hodgkin's lymphoma (NHL), but whether risk varies by family member's gender is unclear. Among 121 216 women participating in the prospective California Teachers Study, NHL risk varied by type of haematopoietic malignancy and gender of the relative.

Adenoidectomy can improve obstructive sleep apnoea in young children: systematic review and meta-analysis.

OBJECTIVE: To systematically search for studies reporting outcomes for adenoidectomy alone as a treatment for paediatric obstructive sleep apnoea and use the data to perform a meta-analysis. METHODS: Nine databases, including PubMed and Medline, were systematically searched through to 1 April 2016. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement was followed. RESULTS: A total of 1032 articles were screened and 126 full texts were reviewed. Three paediatric studies (47 patients) reported outcomes. Overall, apnoea-hypopnoea index values decreased from 18.1 ± 16.8 to 3.1 ± 5.5 events per hour (28 patients). Random-effects modelling demonstrated a mean difference of -14.43 events per hour (I2 = 23 per cent (low inconsistency)). The apnoea-hypopnoea index standardised mean difference was -1.14 (large magnitude of effect). The largest reduction in apnoea-hypopnoea index was observed in children aged less than 12 months (reduction of 56.6-94.9 per cent). Lowest oxygen saturation values improved from 80.0 ± 9.5 to 85.5 ± 6.0 per cent (13 children). CONCLUSION: Adenoidectomy alone has improved obstructive sleep apnoea in children, especially in those aged less than 12 months; however, given the low number of studies, isolated adenoidectomy remains an area for additional research.

Sick leave and disability pension in Hodgkin lymphoma survivors by stage, treatment, and follow-up time--a population-based comparative study.

PURPOSE: This study seeks to investigate the long-term public health burden of Hodgkin lymphoma (HL) in terms of work loss following contemporary treatment protocols and associations with established treatment complications and lymphoma relapse. METHODS: We identified 1,989 Swedish HL patients (1,082 with clinical information) aged 18-60 (median 33) years at diagnosis 1992-2009, and matched 1:4 to population comparators. Sick leave, disability pension (work loss), and comorbidity were retrieved through September 2013. Relative risks (RR) with 95% confidence intervals (CI) were calculated using Poisson regression, and mean lost work days were estimated yearly during follow-up. RESULTS: The risk of annual work loss was elevated in HL survivors versus comparators up to the 15th year post-diagnosis (RR(5th year) 1.64, 95% CI 1.46-1.84; RR(10th year) 1.33, 95% CI 1.15-1.34; and RR(15th year) 1.30, 95% CI 1.04-1.62). The risk remained elevated up to the 10th year after adjustment for secondary malignancies and cardiovascular disease (RR(10th year) 1.31, 95% CI 1.13-1.52). Advanced-stage patients had more lost days than comparators (mean number(5th year) 66 versus 33, mean difference 34, 95% CI 20-48) as did patients receiving 6-8 chemotherapy courses (62 versus 33, mean difference(5th year) 30, 95 % CI 17-43). Among patients in the first complete remission, a difference was still observed for advanced-stage (51 versus 33, mean difference(5th year) 19, 95% CI 5-34) but not early-stage disease. CONCLUSIONS: Advanced-stage HL survivors treated with full-dose chemotherapy were at increased risk of work loss, not only explained by relapse, secondary malignancies, or cardiovascular disease. IMPLICATIONS FOR CANCER SURVIVORS: The results call for increased awareness and evaluation of reasons for long-term work disability following intensive chemotherapy among young HL survivors.

Effects of sibutramine in overweight, poorly controlled Chinese female type 2 diabetic patients: a randomised, double-blind, placebo-controlled study.

To assess the efficacy of sibutramine 15 mg once daily as weight reduction in overweight and obese (body mass index > 25 kg/m2) Chinese female type 2 diabetic patients and to evaluate the influence of weight loss on diabetic control, a randomised, double-blind, placebo-control, 12-week study was conducted. Chinese female type 2 diabetic patients, poorly controlled glucose levels and HbA(1C) > 8% were randomly assigned to two groups. In addition to their hypoglycaemic agents (maximal doses of sulphonylureas and metformin), one group (n = 30) received a sibutramine 15 mg once daily for 12 weeks, and the other (n = 30) received placebo for the same period. Comparing the changes that occurred after 12 weeks in the sibutramine and placebo groups, the former showed significantly greater reduction in body weight (2.5 vs. 0.1 kg, p < 0.05), fasting plasma insulin level (28.8 vs. 2.4 pmol/l, p < 0.01), 2-h postprandial blood glucose after standard test meal (3.2 vs. 1.1 mmol/l, p < 0.01), insulin resistance (5.1 vs. 0.2, p < 0.01), HbA1C (1.7% vs. 0.2%, p < 0.05), triglyceride (0.43 vs. 0.12 mmol/l, p < 0.05) and total cholesterol (0.52 vs. 0.08 mmol/l, p < 0.05). No significant differences were found between treatment groups in blood pressure and heart rate. The addition of sibutramine to diet and oral hypoglycaemic therapy resulted in significant weight loss and improvement in metabolic parameters in the treatment group. Sibutramine should be considered for use alongside diet and oral hypoglycaemic therapy in Chinese overweight and obese women with poorly controlled type 2 diabetes.

A novel 160-kDa phosphotyrosine protein in insulin-treated embryonic kidney cells is a new member of the insulin receptor substrate family.

We have previously identified a 160-kDa protein in human embryonic kidney (HEK) 293 cells that undergoes rapid tyrosine phosphorylation in response to insulin (PY160) (Kuhné, M. R., Zhao, Z., and Lienhard, G. E. (1995) Biochem. Biophys. Res. Commun. 211, 190-197). The phosphotyrosine form of PY160 was purified from insulin-treated HEK 293 cells by anti-phosphotyrosine immunoaffinity chromatography, the sequences of peptides determined, and its cDNA cloned. The PY160 cDNA encodes a 1257-amino acid protein that contains, in order from its N terminus, a pleckstrin homology (PH) domain, a phosphotyrosine binding (PTB) domain, and, spread over the C-terminal portion, 12 potential tyrosine phosphorylation sites. Several of these sites are in motifs expected to bind specific SH2 domain-containing proteins: YXXM (7 sites), phosphatidylinositol 3-kinase; YVNM (1 site), Grb-2; and YIEV (1 site), either the protein-tyrosine phosphatase SHP-2 or phospholipase Cgamma. Furthermore, the PH and PTB domains are highly homologous (at least 40% identical) to those found in insulin receptor substrates 1, 2, and 3 (IRS-1, IRS-2, and IRS-3). Thus, PY160 is a new member of the IRS family, which we have designated IRS-4.

Recombinant acyl-CoA:cholesterol acyltransferase-1 (ACAT-1) purified to essential homogeneity utilizes cholesterol in mixed micelles or in vesicles in a highly cooperative manner.

Acyl-coenzyme A:cholesterol acyltransferase (ACAT) is an integral membrane protein located in the endoplasmic reticulum. It catalyzes the formation of cholesteryl esters from cholesterol and long-chain fatty acyl coenzyme A. The first gene encoding the enzyme, designated as ACAT-1, was identified in 1993 through an expression cloning approach. We isolated a Chinese hamster ovary cell line that stably expresses the recombinant human ACAT-1 protein bearing an N-terminal hexahistidine tag. We purified this enzyme approximately 7000-fold from crude cell extracts by first solubilizing the cell membranes with the zwitterionic detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate, then proceeding with an ACAT-1 monoclonal antibody affinity column and an immobilized metal affinity column. The final preparation is enzymologically active and migrates as a single band at 54 kDa on SDS-polyacrylamide gel electrophoresis. Pure ACAT-1 dispersed in mixed micelles containing sodium taurocholate, phosphatidylcholine, and cholesterol remains catalytically active. The cholesterol substrate saturation curves of the enzyme assayed either in mixed micelles or in reconstituted vesicles are both highly sigmoidal. The oleoyl-coenzyme A substrate saturation curves of the enzyme assayed under the same conditions are both hyperbolic. These results support the hypothesis that ACAT is an allosteric enzyme regulated by cholesterol.

Immunological quantitation and localization of ACAT-1 and ACAT-2 in human liver and small intestine.

By using specific anti-ACAT-1 antibodies in immunodepletion studies, we previously found that ACAT-1, a 50-kDa protein, plays a major catalytic role in the adult human liver, adrenal glands, macrophages, and kidneys but not in the intestine. Acyl-coenzyme A:cholesterol acyltransferase (ACAT) activity in the intestine may be largely derived from a different ACAT protein. To test this hypothesis, we produced specific polyclonal anti-ACAT-2 antibodies that quantitatively immunodepleted human ACAT-2, a 46-kDa protein expressed in Chinese hamster ovary cells. In hepatocyte-like HepG2 cells, ACAT-1 comprises 85-90% of the total ACAT activity, with the remainder attributed to ACAT-2. In adult intestines, most of the ACAT activity can be immunodepleted by anti-ACAT-2. ACAT-1 and ACAT-2 do not form hetero-oligomeric complexes. In differentiating intestinal enterocyte-like Caco-2 cells, ACAT-2 protein content increases by 5-10-fold in 6 days, whereas ACAT-1 protein content remains relatively constant. In the small intestine, ACAT-2 is concentrated at the apices of the villi, whereas ACAT-1 is uniformly distributed along the villus-crypt axis. In the human liver, ACAT-1 is present in both fetal and adult hepatocytes. In contrast, ACAT-2 is evident in fetal but not adult hepatocytes. Our results collectively suggest that in humans, ACAT-2 performs significant catalytic roles in the fetal liver and in intestinal enterocytes.