| Rank |
Pathway / Axis |
Cancer Cells (↑ / ↓ / ↔) |
Normal Cells (↑ / ↓ / ↔) |
TSF |
Primary Effect |
Notes / Interpretation |
| 1 |
One-carbon metabolism (Methionine synthase → SAM) |
↑ methylation capacity; ↑ nucleotide synthesis (proliferation support) |
↑ genome stability; ↑ normal DNA synthesis |
R→G |
Methyl donor cycling |
Supports SAM production; in rapidly dividing tumors may facilitate growth if not limiting. |
| 2 |
DNA methylation / Epigenetics |
↔ / ↑ (context-dependent; can restore normal methylation if deficient) |
↑ methylation homeostasis |
G |
Epigenetic stability |
Deficiency → hypomethylation/genomic instability; supplementation restores baseline rather than inducing supraphysiologic hypermethylation in most settings. |
| 3 |
Nucleotide synthesis (via folate cycle coupling) |
↑ proliferation support (if B12 limiting) |
↑ normal hematopoiesis |
R→G |
DNA replication capacity |
Mechanistically linked to folate; deficiency leads to megaloblastic anemia. |
| 4 |
Mitochondrial metabolism (Methylmalonyl-CoA mutase) |
↔ (supports baseline metabolism) |
↑ mitochondrial function |
R |
Anaplerotic support |
Prevents methylmalonic acid accumulation; preserves mitochondrial efficiency. |
| 5 |
ROS |
↔ (indirect) |
↓ oxidative stress (deficiency correction) |
R |
Redox balance (secondary) |
Effects mediated through improved mitochondrial and methylation balance. |
| 6 |
NRF2 |
↔ (no direct axis) |
↔ |
G |
Adaptive response (indirect) |
No primary NRF2-targeting activity established. |
| 7 |
Ca2+ |
↔ |
↔ |
P |
Not a core pathway |
No meaningful Ca²⁺ modulation axis. |
| 8 |
HIF-1α / Warburg |
↔ (indirect via proliferation capacity) |
↔ |
G |
Metabolic permissiveness |
No direct hypoxia pathway targeting; effects are permissive rather than suppressive. |
| 9 |
Ferroptosis |
↔ |
↔ |
R |
Not established |
No defined ferroptotic mechanism. |
| 10 |
Clinical Translation Constraint |
Essential nutrient; correction of deficiency critical. No validated anticancer benefit; very high serum B12 often reflects disease state rather than supplementation causality. |
— |
Evidence |
Interpret epidemiologic associations cautiously (reverse causation common). |