DNA methylation profiling can classify HIV-associated lymphomas
ABSTRACT HIV-positive patients have a 60-fold to 200-fold increased incidence of non-Hodgkin lymphomas, including Burkitt lymphoma, diffuse large B-cell lymphoma, and primary central nervous system lymphoma. HIV-associated lymphomas frequently have features such as extranodal involvement, decreased responses to standard chemotherapy, and high relapse rates, which indicate a poor prognosis. General pathological features do not clearly differentiate HIV-associated lymphomas from non-HIV lymphomas.
To investigate the features of HIV-associated lymphomas, we performed genome-wide DNA methylation profiling of HIV and non-HIV lymphomas using Illumina GoldenGate Methylation Cancer Panel I and Illumina Infinium HumanMethylation450 BeadChip microarrays. DNA methylation profiles in HIV-associated and non-HIV lymphomas were characterized using unsupervised hierarchical clustering analyses.
The analyses of promoter regions revealed unique DNA methylation profiles in HIV-associated lymphomas, suggesting profile differences compared with non-HIV lymphomas, which implies specific gene regulation in HIV-associated lymphoma involving DNA methylation. Based on HumanMethylation450 BeadChip data, 2541 target sites were selected as differing significantly in comparisons between HIV-associated and non-HIV-associated lymphomas using Wilcoxon's rank-sum test (P <0.05) and Δβ values more than 0.30. Recurrent cases of HIV-associated lymphoma had different profiles compared with nonrecurrent HIV lymphomas.
DNA methylation profiling indicated that 2541 target sites differed significantly in HIV-associated lymphoma, which may partly explain the poor prognosis. Our data indicate that the methylation profiles of target genes have potential in elucidating HIV-associated lymphomagenesis and can serve as new prognostic markers.
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ABSTRACT: We describe the anatomic and histologic presentation and prognosis of non-Hodgkin's lymphoma (NHL) among people with AIDS (PWA) and determine their contribution to the NHL burden. We linked AIDS and cancer registries in selected areas of the United States and compared NHL sites and histologies in PWA and non-PWA, after adjusting for age, sex and ethnicity. Among 51,033 PWA, we found 2,156 cases of NHL (4.3%). Half of NHL cases occurring post-AIDS were not reported to AIDS registries. NHL was part of an AIDS-defining condition for 3.2% of all PWA; the relative risk of NHL with 3.5 years of another AIDS diagnosis was 165-fold compared to non-PWA within the cancer surveillance system. Of NHLs, 39% were high grade (vs. 12% among non-PWA), 60% were nodal (vs. 74% among non-PWA) and 15% had brain primaries (vs. 1% among non-PWA). Excluding brain sites, extranodal sites were still 20% more common than expected. Relative risk was elevated for all histologic types, with the risk ranging from 652-fold for high-grade diffuse immunoblastic tumors and 261-fold for Burkitt's lymphomas to 113 for intermediate-grade lymphoma to 14-fold for low-grade lymphoma. Survival among PWA with NHL was poor, and tumor grade had little impact. In high-risk AIDS areas, AIDS-related NHLs constitute a major share of the NHL burden. We conclude that NHL risk is considerably under-estimated in AIDS registry data. The major differences between PWA and non-PWA were the high frequency of brain lymphoma and the increase in high-grade lymphomas in PWA. However, the grade of NHL did not influence the prognosis among PWA with lymphoma. The increasing risk of NHL in PWA has contributed substantially to the general increase in NHL rates in the United States since 1981.International Journal of Cancer 12/1997; 73(5):645-50. · 5.01 Impact Factor
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ABSTRACT: High serum concentrations of vascular endothelial growth factor (S-VEGF) and basic fibroblast growth factor (S-bFGF) are associated with unfavorable clinical characteristics in cancer. The combined effect of S-VEGF and S-bFGF on the survival of 200 patients with non-Hodgkin lymphoma (NHL) was studied. High S-VEGF and S-bFGF at diagnosis were associated with poor survival with the medians, the highest tertiles, or the highest quartiles as the cutoff values. The highest prognostic power was obtained when S-VEGF and S-bFGF were examined as a combination. Patients who had both S-VEGF and S-bFGF within the highest quartiles had only a 21% 5-year survival rate in contrast to a 64% 5-year survival rate among patients with both factors within the 3 lowest quartiles (P <.0001). Simultaneous elevation of S-VEGF and S-bFGF was associated with poor survival in different grades of lymphomas and in the largest histologic subgroup, the large-cell diffuse and immunoblastic lymphomas. S-VEGF (relative risk [RR], 1.83; P =.019) and S-bFGF (RR, 2.02; P =.0049) had independent influences on survival in multivariate models when tested together with the components of the International Prognostic Index (IPI). Patients with both S-VEGF and S-bFGF within the highest quartiles had nearly 3 times higher risk for death (RR, 2.90; 95% confidence interval [CI], 1.56-5.40; P =.0008) than the rest of the patients. This RR was higher than the relative risks associated with any of the components of the IPI in the same model. The authors conclude that the combination of S-VEGF and S-bFGF is a powerful prognostic variable in NHL. (Blood. 2000;96:3712-3718)Blood 12/2000; 96(12):3712-8. · 9.78 Impact Factor
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ABSTRACT: A variety of tumor suppressor genes are down-regulated by hypermethylation during carcinogenesis. Using methylated CpG amplification-representation difference analysis, we identified a DNA fragment corresponding to the Tazarotene-induced gene 1 (TIG1) promoter-associated CpG island as one of the genes hypermethylated in the leukemia cell line K562. Because TIG1 has been proposed to act as a tumor suppressor, we tested the hypothesis that cytosine methylation of the TIG1 promoter suppresses its expression and causes a loss of responsiveness to retinoic acid in some neoplastic cells. We examined TIG1 methylation and expression status in 53 human cancer cell lines and 74 primary tumors, including leukemia and head and neck, breast, colon, skin, brain, lung, and prostate cancer. Loss of TIG1 expression was strongly associated with TIG1 promoter hypermethylation (P < 0.001). There was no correlation between TIG1 promoter methylation and that of retinoid acid receptor beta2 (RARbeta2), another retinoic-induced putative tumor suppressor gene (P = 0.78). Treatment with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine for 5 days restored TIG1 expression in all eight silenced cell lines tested. TIG1 expression was also inducible by treatment with 1 micro M all-trans-retinoic acid for 3 days except in densely methylated cell lines. Treatment of the K562 leukemia cells with demethylating agent combined with all-trans-retinoic acid induced apoptosis. These findings indicate that silencing of TIG1 promoter by hypermethylation is common in human cancers and may contribute to the loss of retinoic acid responsiveness in some neoplastic cells.Cancer Research 04/2004; 64(7):2411-7. DOI:10.1158/0008-5472.CAN-03-0164 · 9.28 Impact Factor