Our data agree with the hypothesis of a gene-nutrient interaction between MTHFR 677C-->T polymorphism and folate status that may confer a selective advantage of TT-homozygous genotype when dietary intake of folate is adequate, at least in the areas studied.

Transcobalamin (TC) is the plasma transporter that delivers vitamin B(12) to cells. We have already reported that HT-29 and Caco-2 cells secrete different TC variants. HT-29 secretes 2 TC isoproteins (codon 259-Pro/Arg [259-P/R]), exhibiting unequal concentrations (TC 259-P > TC 259-R), and Caco-2 cells only secrete the phenotype 259-R. We investigated the relation between phenotypic and genetic TC polymorphism in HT-29 cells transfected with Caco-2 TC complementary DNA and in 159 healthy Caucasians. We found that codon 259-R is buried and, thus, the genetic polymorphism provides no explanation why the TCs from HT-29 and Caco-2 cells have different isoelectric points in nondenaturing isoelectric focusing (IEF). The newly translated TC in HT-29 cells from the Caco-2 complementary DNA recombinant plasmid had the same isoelectric point as the TC constitutively expressed in HT-29 cells, suggesting that TC phenotypic variability involves a specific cell folding of the protein. The codon 259 polymorphism was found to have a biallelic distribution: homozygotes P = 34.6%, heterozygotes R/P = 47.8%, and homozygotes R = 17.6%. In heterozygous samples, the IEF showed that the TC 259-P/TC 259-R ratio = 1.6. The blood apo-TC concentration of 259-P homozygous Caucasians was significantly higher than that of homozygous 259-R (P <.0001) and heterozygous (P <.0006) Caucasians. The heterozygotes 259-R/P had homocysteine concentration significantly higher than the homozygotes 259-R and 259-P (P =.02 and P =.01, respectively). In conclusion, TC codon-259 polymorphism affects TC plasma concentration and may interfere in vitamin B(12) cellular availability and homocysteine metabolism.

SummaryBackgroundPatients with cirrhosis are at high risk of hepatocellular carcinoma (HCC). The SEPT9 gene is a key regulator of cell division and tumor suppressor whose hypermethylation is associated with liver carcinogenesis. The primary aim of this study was to evaluate the diagnostic accuracy of a PCR-based assay for the analysis of SEPT9 promoter methylation in circulating cell-free DNA (mSEPT9) for diagnosing HCC among cirrhotic patients.MethodsWe report two phase II biomarker studies that included cirrhotic patients with or without HCC from France (initial study) and Germany (replication study). All patients received clinical and biological evaluations, and liver imaging according to current recommendations. The primary outcome was defined as the presence of HCC according to guidelines from the American Association for the Study of Liver Diseases. The diagnosis of HCC was confirmed by abdominal contrast-enhanced computed tomography scan and systematically discussed in a multidisciplinary consultation meeting. HCC-free cirrhotic patients were recruited if the screening abdominal ultrasound showed no evidence of HCC at the time of blood sampling for the mSEPT9 test and on the next visit six months later. The adjudicating physicians were blinded to patient results associated with the mSEPT9 test.FindingsWe included 289 patients with cirrhosis (initial: 186; replication: 103), among whom 98 had HCC (initial: 51; replication: 47). The mSEPT9 test exhibited high diagnostic accuracy for HCC diagnosis, with an area under the receiver operating characteristic curve (AUROC) of 0.944 (0.900–0.970, p < 0.0001) in the initial study (replication: 0.930 [0.862–0.971, p < 0.0001]; meta-analysis: AUROC = 0.940 [0.910–0.970, p < 0.0001], no heterogeneity: I2 = 0%, p = 0.67; and no publication bias). In multivariate logistic regression analysis, the number of positive mSEPT9 triplicates was the only independent variable significantly associated with HCC diagnosis (initial: OR = 6.30, for each mSEPT9 positive triplicate [2.92–13.61, p < 0.0001]; replication: OR = 6.07 [3.25–11.35, p < 0.0001]; meta-analysis: OR = 6.15 [2.93–9.38, p < 0.0001], no heterogeneity: I2 = 0%, p = 0.95; no publication bias). AUROC associated with the discrimination of the logistic regression models in initial and validation studies were 0.969 (0.930–0.989) and 0.942 (0.878–0.978), respectively, with a pooled AUROC of 0.962 ([0.937–0.987, p < 0.0001], no heterogeneity: I2 = 0%, p = 0.36; and no publication bias).InterpretationAmong patients with cirrhosis, the mSEPT9 test constitutes a promising circulating epigenetic biomarker for HCC diagnosis at the individual patient level. Future prospective studies should assess the mSEPT9 test in the screening algorithm for cirrhotic patients to improve risk prediction and personalized therapeutic management of HCC.

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