Citations

Abstract Context: Environmental exposure to herbicides has been hypothesized to contribute to the long-term increase in non-Hodgkin lymphoma (NHL). Objective: To estimate the effects of residential herbicide exposure on NHL risk. Design: Population-based case-control study. Setting: Iowa and metropolitan Detroit, Los Angeles, and Seattle, 1998 to 2000. Participants: NHL patients ages 20 to 74 years and unaffected residents identified by random digit dialing and Medicare eligibility files. Main Outcome Measures: Computer-assisted personal interviews (1,321 cases, 1,057 controls) elicited data on herbicide use at each home occupied since 1970. Levels of 2,4-dichlorophenoxy-acetic acid and dicamba were measured in dust taken from used vacuum cleaner bags in the current home (679 cases, 510 controls who had owned at least half of their carpets for ≥5 years). Results: Herbicide use on the lawn or garden was similar among cases and controls (adjusted relative risk, 1.02; 95% confidence interval, 0.84-1.23). Estimated risk did not increase with greater duration, frequency, or total number of applications of herbicides to the lawn, the garden, or to both combined. Risk was not elevated for respondents who applied the herbicides themselves and not for those exposed during the 1970s, 1980s, or 1990s. We detected 2,4-dichlorophenoxy-acetic acid equally often in homes of cases and controls (78%). We found dicamba in homes of 15% of cases and 20% of controls. We also found no elevation in risk among the respondents who had the highest dust levels and highest self-reported exposures. We found no consistent patterns for specific histologies. Conclusions: We found no detectable excess associated with residential exposures. Residential herbicide exposures are unlikely to explain the long-term increase in NHL.

Abstract Background: The International Lymphoma Epidemiology Consortium (InterLymph) provides an opportunity to analyze the relationship between cigarette smoking and non-Hodgkin lymphoma with sufficient statistical power to consider non-Hodgkin lymphoma subtype. The results from previous studies of this relationship have been inconsistent, likely due to the small sample sizes that arose from stratification by disease subtype. To clarify the role of cigarette smoking in the etiology of non-Hodgkin lymphoma, we conducted a pooled analysis of original patient data from nine case-control studies of non-Hodgkin lymphoma conducted in the United States, Europe, and Australia. Methods: Original data were obtained from each study and uniformly coded. Risk estimates from fixed-effects and two-stage random-effects models were compared to determine the impact of interstudy heterogeneity. Odds ratios (OR) and 95% confidence intervals (95% CI) were derived from unconditional logistic regression models, controlling for study center, age, sex, and race. Results: In our pooled study population of 6,594 cases and 8,892 controls, smoking was associated with slightly increased risk estimates (OR, 1.07; 95% CI, 1.00-1.15). Stratification by non-Hodgkin lymphoma subtype revealed that the most consistent association between cigarette smoking and non-Hodgkin lymphoma was observed among follicular lymphomas (n = 1452). Compared with nonsmokers, current smokers had a higher OR for follicular lymphoma (1.31; 95% CI, 1.12-1.52) than former smokers (1.06; 95% CI, 0.93-1.22). Current heavy smoking (≥36 pack-years) was associated with a 45% increased OR for follicular lymphoma (1.45; 95% CI, 1.15-1.82) compared with nonsmokers. Conclusions: Cigarette smoking may increase the risk of developing follicular lymphoma but does not seem to affect risk of the other non-Hodgkin lymphoma subtypes we examined. Future research is needed to determine the biological mechanism responsible for our subtype-specific results.

Abstract A possible role for SV40, a macaque polyomavirus, in non-Hodgkin lymphoma (NHL) in humans was raised recently by the reported detection of SV40 DNA in tumor tissue. Animals with SV40-induced tumors frequently produce high-level antibodies against T antigen, the SV40 oncoprotein. In this study, we assessed whether SV40 T antibody measured in humans supported a relationship between SV40 and NHL. Subjects were sampled from a U.S. population-based case-control study of NHL, according to presence of antibodies against capsids of SV40 and BK, a related human polyomavirus (n = 85 cases, n = 95 controls). T antibody was measured by enzyme immunoassay. We also evaluated serum specimens from SV40-infected and SV40-uninfected macaques (n = 19 and n = 8, respectively), SV40-uninfected hamsters (n = 5), and hamsters with SV40-induced tumors (n = 10). Hamsters with SV40-induced tumors all produced robust SV40 T antibody [median absorbance, 0.99), whereas SV40-uninfected hamsters and macaques had much lower levels (median absorbance, 0.05 and 0.04, respectively). NHL cases, controls, and SV40-infected macaques resembled these latter two groups, generally showing only low-level T antibody (median absorbance, 0.03, 0.04, and 0.04, respectively). Overall, only five cases (6%) and five controls (5%) had T antibody responses classified as seropositive (odds ratio, 1.2; 95% confidence interval, 0.3-4.6). Interestingly, all 10 humans with T antibody responses also showed antibody responses to BK capsid. We found no association between the presence of T antibody and NHL, arguing against SV40 as a cause of NHL. Infrequent and low-level T antibody responses among humans could represent cross-reactivity to BK virus T antigen.

Genome-wide variance components linkage analysis was performed on 4 latent factors underlying metabolic syndrome derived from 10 risk factors. The latent factors represent obesity and insulin, blood pressure, lipids and insulin, and central obesity. The metabolic syndrome factor scores were derived in 4 ethnic groups recruited in 3 Networks of the Family Blood Pressure Program: GENOA (blacks, Hispanics, and whites), HyperGEN (blacks and whites), SAPPHIRe (Asians). Heritabilities of metabolic syndrome factors ranged from 66% for obesity and insulin to 11% for blood pressure factor. We observed higher heritabilities for obesity and insulin, and lipids and insulin, whereas those for blood pressure and central obesity were smaller. Linkage analysis detected two major quantitative trait loci. One of them linked to the obesity and insulin factor with a lod score of 3.94 ( P =0.00001, marker GATA11A06, D18S53, 41.24 cM) at marker positions linkage (lod 4.71, at 46.84 cM at 1-cM-apart distances linkage), located on chromosome 18p11.21 in GENOA black. The other linked to the blood pressure factor with a lod score of 3.22 ( P =0.000059, marker GATA49C09, D17S1290, 82 cM) at marker positions linkage (lod 3.56, at 84.63 cM for 1 cM apart distances linkage) located on chromosome 17q23.1 in Hispanics. These quantitative trait loci, together with 4 additional ones with lod scores >2.5, and 30 additional ones with lod score >1.7, offer hope for dissecting the genetic architecture of metabolic syndrome with beneficial implications for molecular diagnosis, prognosis, and in potential medical intervention.

AbstractWe have reported that i.d. injection of plasmids encoding hsp70 and a suicide gene transcriptionally targeted to melanocytes generates specific proinflammatory killing of melanocytes. The resulting CD8+ T cell response eradicates systemically established B16 tumors. Here, we studied the consequences of that CD8+ T cell response on the phenotype of preexisting tumor. In suboptimal protocols, the T cell response selected B16 variants, which grow extremely aggressively, are amelanotic and have lost expression of the tyrosinase and tyrosinase-related protein 2 (TRP-2) antigens. However, expression of other melanoma-associated antigens, such as gp100, was not affected. Antigen loss could be reversed by long-term growth in culture away from immune-selective pressures or within 96 hours by treatment with the demethylating agent 5-azacytidine (5-Aza). When transplanted back into syngeneic animals, variants were very poorly controlled by further vaccination. However, a combination of vaccination with 5-Aza to reactivate antigen expression in tumors in situ generated highly significant improvements in therapy over treatment with vaccine or 5-Aza alone. These data show that inflammatory killing of normal cells activates a potent T cell response targeted against a specific subset of self-antigens but can also lead to the immunoselection of tumor variants. Moreover, our data indicate that emergence of antigen loss variants may often be due to reversible epigenetic mechanisms within the tumor cells. Therefore, combination therapy using vaccination and systemic treatment with 5-Aza or other demethylating agents may have significant therapeutic benefits for antitumor immunotherapy.

Abstract Glycosphingolipids are known to play roles in integrin-mediated cell adhesion and migration; however, the mechanisms by which glycosphingolipids affect integrins are unknown. Here, we show that addition of the glycosphingolipid, C8-lactosylceramide (C8-LacCer), or free cholesterol to human fibroblasts at 10°C causes the formation of glycosphingolipid-enriched plasma membrane domains as shown by visualizing a fluorescent glycosphingolipid probe, BODIPY-LacCer, incorporated into the plasma membrane of living cells. Addition of C8-LacCer or cholesterol to cells initiated the clustering of β1-integrins within these glycosphingolipid-enriched domains and the activation of the β1-integrins as assessed using a HUTS antibody that only binds activated integrin. On warming to 37°C, β1-integrins were rapidly internalized via caveolar endocytosis in cells treated with C8-LacCer or cholesterol, whereas little β1-integrin was endocytosed in untreated fibroblasts. Incubation of cells with C8-LacCer or cholesterol followed by warm-up caused src activation, a reorganization of the actin cytoskeleton, translocation of RhoA GTPase away from the plasma membrane as visualized using total internal reflection fluorescence microscopy, and transient cell detachment. These studies show that LacCer can regulate integrin function both by modulating integrin clustering in microdomains and by regulating integrin endocytosis via caveolae. Our findings suggest the possibility that aberrant levels of glycosphingolipids found in cancer cells may influence cell attachment events by direct effects on integrin clustering and internalization.

AbstractApproximately 5% of rectal cancers are locally advanced with adherence to the vagina, uterus, bladder, prostate, or other structures. Sacral involvement is fortunately rare in primary cancers. In about 50% of patients there is histologic confirmation of tumor invasion in the area of adherence. It is important to recognize the nature of these tumors pre‐operatively so that the patient can be prepared for an exenterative procedure should this be necessary. When these tumors are removeden bloc, 5‐year survival rates of 50% can be obtained with survival depending on the presence or absence of regional metastasis and also the presence or absence of histologic tumor invasion into adjacent structures.