Methylenetetrahydrofolate reductase C677T genotype affects promoter methylation of tumor-specific genes in sporadic colorectal cancer through an interaction with folate/vitamin B12 status
Bibliographic record
Abstract
AIM: To evaluate joint effects of Methylentetra-hydrofolate reductase (MTHFR) C677T genotypes, and serum folate/vitamin B(12) concentrations on promoter methylation of tumor-associated genes among Iranian colorectal cancer patients. METHODS: We examined the associations between MTHFR C677T genotype, and promoter methylation of P16, hMLH1, and hMSH2 tumor-related genes among 151 sporadic colorectal cancer patients. The promoter methylation of tumor-related genes was determined by methylation-specific PCR. Eighty six patients from whom fresh tumor samples were obtained and 81 controls were also examined for serum folate and vitamin B(12) concentrations by a commercial radioimmunoassay kit. RESULTS: We found 29.1% of cases had tumors with at least one methylated gene promoter. In case-case comparison, we did not find a significant association between methylation in tumors and any single genotype. However, in comparison to controls with the CC genotype, an increased risk of tumor methylation was associated with the CT genotype (OR = 2.5; 95% CI, 1.1-5.6). In case-case comparisons, folate/vitamin B(12) levels were positively associated with tumor methylation. Adjusted odds ratios for tumor methylation in cases with high (above median) versus low (below median) serum folate/vitamin B(12) levels were 4.9 (95% CI, 1.4-17.7), and 3.9 (95% CI, 1.1-13.9), respectively. The frequency of methylated tumors was significantly higher in high methyl donor than low methyl donor group, especially in those with MTHFR CT (P = 0.01), and CT/TT (P = 0.002) genotypes, but not in those with the CC genotype (P = 1.0). CONCLUSION: We conclude that high concentrations of serum folate/vitamin B(12) levels are associated with the risk of promoter methylation in tumor-specific genes, and this relationship is modified by MTHFR C677T genotypes.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".