Prognostic assessment of three single-nucleotide polymorphisms (GNB3 825C>T, BCL2-938C>A, MCL1-386C>G) in extrahepatic cholangiocarcinoma
Department of Gastroenterology and Hepatology, University Hospital of Essen, Germany. Cancer Investigation
(Impact Factor: 2.22).
12/2009; 28(5):472-8. DOI: 10.3109/07357900903095714
Cholangiocellular carcinoma (CCA) has a devastating prognosis and markers enabling a precise prediction of the clinical outcome have long remained scarce. Recently, it has been demonstrated that genotype distribution of several single-nucleotide polymorphisms (SNPs) in genes that modulate G protein-signal transduction and apoptosis can serve as helpful predictive parameters in various carcinomas. We here aimed at extending the panel of SNPs suitable for predicting the outcome of CCA.
Forty Caucasian patients with extrahepatic CCA and 40 age- and sex-matched healthy white Caucasians were genotyped to elucidate putative associations between clinical outcome and genotypes of the three following SNPs: G protein beta 3 (GNB3) 825C>T, B-cell-lymphoma-2 (Bcl-2) -938C>A, and myeloid cell leukemia-1 (Mcl-1) -386C>G.
Patients homozygous for the C allele of the GNB3 825C>T polymorphism exhibited a significant prolonged overall survival compared with patients displaying the CT or TT genotype (median survival [months]: 31 vs. 13 vs. 7; p < .05) and also showed lower bilirubin serum levels. Additionally, the CC genotype of the BCL2-938C>A polymorphism was associated with higher GLDH serum activities (U/l; 29.8 +/- 7.1 vs. 11.4 +/- 4.3 vs. 5.6 +/- 1.7 comparing CC vs. CA vs. AA; p < .05). Genotype distributions for all SNPs were not significantly different in patients vs. controls.
GNB3 825C>T SNP may be a novel independent prognostic marker for patients suffering from extrahepatic CCA with the CC genotype to be associated with a favorable clinical outcome. Further prospective studies are needed to confirm these results and reveal additional functional SNP effects.
Available from: Benjamin Juntermanns
- "In addition, expression of biomarkers such as vascular endothelial growth factor A and metallothionein has been shown to correlate with survival of patients suffering from extrahepatic cholangiocarcinoma.16,17 In a recent report, patients homozygous for the C allele of the GNB3 825C>T single nucleotide polymorphism exhibited a significantly prolonged survival compared with patients heterozygous for this polymorphism or lacking the C allele.18 However, the prognostic value of these markers will have to be prospectively confirmed before they can be applied to patient selection for adjuvant therapy regimens. "
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The seventh edition of the TNM classification separates extrahepatic bile duct tumors into perihilar and distal tumors and further changes the definition of the TNM classification. The impact of the seventh edition on stage-based prognostic prediction for patients with perihilar cholangiocarcinoma was evaluated.
Between January 1998 and March 2010, 223 consecutive patients with perihilar cholangiocarcinoma underwent surgery at the West German Cancer Center. Median survival times were calculated for the 195 evaluable patients (excluding those with in-hospital mortality) after separate classification by both sixth and seventh editions.
Median overall survival was increased in patients classified using the seventh compared with the sixth edition (UICC I: 56.5 vs 23.75 months; II: 45.9 vs 31.6 months; III: 21.3 vs. 8.76 months; IV: 7.03 vs 5.93 months). The T category of the seventh edition did not alter median survival times of T1 (54.07 months) and T4 (7.83 months) cases, but median survival was prolonged for T2 patients (29.4 vs 31.6 months), and shortened for T3 patients (19.43 vs 11.8 months) staged using the seventh edition. According to Cox proportional hazards regression analysis, patient survival was better predicted by the seventh edition UICC stage and pT categories (p = 0.0014 and p = 0.0396, respectively), than the corresponding sixth edition categories (p = 0.4376 and p = 0.0926, respectively).
The UICC seventh edition TNM classification for perihilar cholangiocarcinoma improves separation of patients with intermediate stage tumors compared with the sixth edition. The prognostic value of the UICC staging system has been strengthened by the introduction of the seventh edition.
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ABSTRACT: Heterotrimeric guanine-binding proteins (G proteins) transmit signals from the cell surface to intracellular signal cascades and are involved in various physiological and pathophysiological processes. Polymorphisms in the genes GNB3 (encoding the Gβ3 subunit), GNAS (encoding the Gαs subunit) and GNAQ (encoding the Gαq subunit) have been the primary focus of investigation. Polymorphisms in these genes could be associated with different complex phenotypes underlining that alterations in G-protein signaling can cause multiple disorders. G proteins present a point of convergence or 'bottleneck' between various receptors and effectors, thus making them a sensible tool for pharmacogenetic studies. The pharmacogenetic studies performed to date mostly demonstrate an association between G-protein polymorphisms and response to therapy or occurrence of adverse drug effects. Therefore, polymorphisms in genes encoding G-protein subunits may help to individualize drug treatment in various diseases with regard to both efficacy and safety.
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ABSTRACT: Cholangiocarcinoma (CC) is increasing in incidence, but its pathogenesis remains poorly understood. Chronic inflammation of the bile duct and cholestasis are major risk factors, but most cases in the West are sporadic. Genetic polymorphisms in biliary transporter proteins have been implicated in benign biliary disease and, in the case of progressive familial cholestasis, have been associated with childhood onset of CC. In the current study, five biologically plausible candidate genes were investigated: ABCB11 (BSEP), ABCB4 (MDR3), ABCC2 (MRP2), ATP8B1 (FIC1) and NR1H4 (FXR).
DNA was collected from 172 Caucasian individuals with confirmed CC. A control cohort of healthy Caucasians was formed. Seventy-three SNPs were selected using the HapMap database to capture genetic variation around the five candidate loci. Genotyping was undertaken with a competitive PCR-based system. Confirmation of Hardy-Weinberg equilibrium and Cochran-Armitage trend testing were performed using PLINK. Haplotype frequencies were compared using haplo.stats.
All 73 SNPs were in Hardy-Weinberg equilibrium. Four SNPs in ABCB11 were associated with altered susceptibility to CC, including the V444A polymorphism, but these associations did not retain statistical significance after Bonferroni correction for multiple testing. Haplotype analysis of the genotyped SNPs in ATP8B1 identified significant differences in frequencies between cases and controls (global p value of 0.005).
Haplotypes in ATP8B1 demonstrated a significant difference between CC and control groups. There was a trend towards significant association of V444A with CC. Given the biological plausibility of polymorphisms in ABCB11 and ATP8B1 as risk modifiers for CC, further study in a validation cohort is required.
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