Pathways towards indolent B-cell lymphoma - Etiology and therapeutic strategies.

Although patients with indolent B-cell lymphomas have a relatively good survival rate, conventional chemotherapy is not curative. Disease courses are typically characterized by multiple relapses and progressively shorter response duration with subsequent lines of therapy. There has been an explosion of innovative targeted agents in the past years. This review discusses current knowledge on the etiology of indolent B-cell lymphomas with respect to the role of micro-organisms, auto-immune diseases, and deregulated pathways caused by mutations. In particular, knowledge on the mutational landscape of indolent B-cell lymphomas has strongly increased in recent years and harbors great promise for more accurate decision making in the current wide range of therapeutic options. Despite this promise, only in chronic lymphocytic leukemia the detection of TP53 mutations and/or del17p currently have a direct effect on treatment decisions. Nevertheless, it is expected that in the near future the role of genetic testing will increase for prediction of response to targeted treatment as well as for more accurate prediction of prognosis in indolent B-cell lymphomas.

Trans fatty acid intake is associated with increased risk and n3 fatty acid intake with reduced risk of non-hodgkin lymphoma.

We evaluated the association of dietary fat and protein intake with risk of non-Hodgkin lymphoma (NHL) in a clinic-based study in 603 cases (including 218 chronic lymphocytic leukemia/small lymphocytic lymphoma, 146 follicular lymphoma, and 105 diffuse large B-cell lymphoma) and 1007 frequency-matched controls. Usual diet was assessed with a 128-item food-frequency questionnaire. Unconditional logistic regression was used to estimate ORs and 95% CIs, and polytomous logistic regression was used to assess subtype-specific risks. trans Fatty acid (TFA) intake was positively associated with NHL risk [OR = 1.60 for highest vs. lowest quartile (95% CI = 1.18, 2.15); P-trend = 0.0014], n3 (ω3) fatty acid intake was inversely associated with risk [OR = 0.48 (95% CI = 0.35, 0.65); P-trend < 0.0001], and there was no association with total, animal, plant-based, or saturated fat intake. When examining intake of specific foods, processed meat [OR = 1.37 (95% CI = 1.02, 1.83); P-trend = 0.03], milk containing any fat [OR = 1.47 (95% CI = 1.16, 1.88); P-trend = 0.0025], and high-fat ice cream [OR = 4.03 (95% CI = 2.80, 5.80); P-trend < 0.0001], intakes were positively associated with risk, whereas intakes of fresh fish and total seafood [OR = 0.61 (95% CI = 0.46, 0.80); P-trend = 0.0025] were inversely associated with risk. Overall, there was little evidence for NHL subtype-specific heterogeneity. In conclusion, diets high in TFAs, processed meats, and higher fat dairy products were positively associated with NHL risk, whereas diets high in n3 fatty acids and total seafood were inversely associated with risk.

Folate deficiency induces genomic uracil misincorporation and hypomethylation but does not increase DNA point mutations.

BACKGROUND AND AIMS: Epidemiologic studies have linked nutritional folate deficiency to an increased risk of cancer, but recent trials suggest that folate supplementation does not protect against tumor formation. Our aim was to analyze the genetic and epigenetic consequences of folate deficiency and to investigate whether impairment of the uracil base excision repair pathway can enhance its effects. METHODS: Wild-type mice and those deficient in uracil DNA glycosylase (Ung(-/-)) were placed on a folate-deficient diet for 8 months. We measured tumor incidence in major organs, DNA mutation rates, DNA mutation spectra, local DNA methylation, and global DNA methylation in colon epithelial cells. RESULTS: The experimental diet increased plasma homocysteine (60%, P< .001) and DNA uracil content (24%, P< .05) but not tumor formation. Global DNA methylation was slightly decreased in splenocytes (9.1%) and small intestinal epithelial cells (4.2%), and significantly reduced in colon epithelial cells (7.2%, P< .04). No gene-specific changes in methylation were detected at the mouse B1 element, the H19 DMR, or the Oct4 gene. By lambda CII assay and sequencing analysis of 730 mutants, we found that Ung(-/-) mice had a higher frequency of point mutations and increased C:G to T:A transitions at non-CpG sites. However, folate deficiency had no additional effect on the DNA mutation frequency or spectrum in Ung(-/-) or wild-type mice. CONCLUSIONS: Contradicting current concepts, these findings indicate that the effects of a low-folate diet on DNA methylation and point mutations are insufficient to promote tumor development, even in the presence of Ung deficiency.