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- Odin, Elisabeth, 1955, et al.
(författare)
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Expression and clinical significance of methylenetetrahydrofolate reductase in patients with colorectal cancer
- 2006
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Ingår i: Clin Colorectal Cancer. - 1533-0028. ; 5:5, s. 344-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The aim of the study was to investigate the influence of methylenetetrahydrofolate reductase (MTHFR) gene expression levels and MTHFR polymorphism C677T on the outcome of patients with colorectal cancer (CRC). Furthermore, we wanted to evaluate the interaction between MTHFR and thymidylate synthase (TS) and folylpolyglutamate synthase (FPGS) and to investigate the impact of folate concentration on patients with CRC with different MTHFR genotypes. PATIENTS AND METHODS: The frequency of MTHFR polymorphism C677T was determined (n = 147), and gene expression levels of MTHFR, TS, and FPGS were quantified with real-time polymerase chain reaction (n = 157). Reduced folates in tissue were measured with a binding assay (n = 40). RESULTS: We observed a significantly lower concentration of tetrahydrofolate (THF) in patients with CT or TT genotypes compared with patients having the CC genotype. Twenty-six patients with Dukes A to C tumors who had not been subjected to chemotherapy relapsed. Out of these, 18 had CT or TT genotypes, and only 8 had the CC genotype (P = 0.045). Furthermore, 75 patients did not relapse, and out of these, 35 had CT or TT genotypes, and 40 had the CC genotype. The relative gene expression level of MTHFR in patients subgrouped by CC and CT or TT genotypes was significantly lower in carcinomas compared with adjacent mucosa (P < 0.0001 and P < 0.0001, respectively). A significant difference in MTHFR expression level was also observed according to MTHFR genotype in the tumor but not in adjacent mucosa. The MTHFR gene expression level in mucosa was a prognostic parameter independent of the clinicopathologic factors with regard to survival for patients with MTHFR C677T mutation. CONCLUSION: Our results showed that it is possible to identify patients with CRC with a higher risk for relapse. Furthermore, patients with a mutant genotype in combination with low MTHFR expression have a poor clinical outcome.
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| 2. |
- Wettergren, Yvonne, 1957, et al.
(författare)
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Low expression of reduced folate carrier-1 and folylpolyglutamate synthase correlates with lack of a deleted in colorectal carcinoma mRNA splice variant in normal-appearing mucosa of colorectal carcinoma patients
- 2005
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Ingår i: Cancer Detect Prev. - : Elsevier BV. - 0361-090X .- 1525-1500. ; 29:4, s. 348-55
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Cellular folate deficiency leads to DNA strand breaks, mutations, and aberrant methylation and might be a risk factor for colorectal cancer (CRC). The putative tumor suppressor gene deleted in colorectal carcinoma (DCC) is one of several genes the expression of which seems to be affected by the folate concentration at the tissue level. Decreased expression of DCC may be caused by LOH or hypermethylation, i.e. by events that might be linked to folate deficiency. The purpose of this study was to analyze if the folate level and the gene expression levels of reduced folate carrier (RFC-1) and folylpolyglutamate synthase (FPGS) had impact on the expression of DCC splice variants. METHODS: Quantification of RFC-1 and FPGS expression in mucosa of 53 CRC patients was performed using real-time PCR whereas DCC splicing variants were detected by automated capillary gel electrophoresis. Total reduced folate concentration was measured with the FdUMP-binding assay (n = 22). RESULTS: Significantly higher expression levels of RFC-1 (p = 0.026) and FPGS (p = 0.05) were found in mucosa expressing the splice variant DCC342 compared to mucosa that did not. Furthermore, multivariate analysis showed that RFC-1 and FPGS (r = 0.49, p = 0.01) as well as folate and RFC-1 (r = 0.56, p = 0.023) were correlated only in mucosa expressing DCC342. CONCLUSIONS: In conclusion, the present study points to a potential influence of folates in regulating DCC expression at multiple levels involving post-transcriptional pathways. The results may provide a basis for a detailed investigation of molecular mechanisms involved in folate regulation of DCC expression.
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