| Rank |
Pathway / Axis |
Cancer / Tumor Context |
Normal Tissue Context |
TSF |
Primary Effect |
Notes / Interpretation |
| 1 |
VDR nuclear signaling (calcitriol → VDR/RXR → gene regulation) |
Differentiation ↑; proliferative drive ↓ (reported) |
Homeostatic gene regulation across many tissues |
R, G |
Transcriptional reprogramming |
Core biology is hormone-like gene regulation; many downstream “anti-cancer” effects are VDR-mediated and context-dependent. |
| 2 |
Cell-cycle braking (p21/p27; Cyclin/CDK tone) |
Cell-cycle arrest ↑ (reported) |
↔ / growth control support |
G |
Cytostasis |
Often described as downstream of VDR transcriptional programs; strength varies widely by tumor type and VDR expression. |
| 3 |
Apoptosis / differentiation programs |
Apoptosis ↑ and/or differentiation ↑ (reported) |
↔ |
G |
Phenotype shift |
Observed in many preclinical models; not a universal direct cytotoxin signature. |
| 4 |
Immune modulation (innate/adaptive tone) |
Anti-inflammatory immune tone ↑ (context); microenvironment effects (reported) |
Immune regulation support |
R, G |
Immunomodulation |
Vitamin D signaling is active in both innate and adaptive immunity; effects depend on baseline status and context. |
| 5 |
NF-κB / inflammatory transcription (downstream) |
Inflammatory programs ↓ (reported) |
Inflammation tone ↓ (context) |
R, G |
Anti-inflammatory signaling |
Commonly reported as a downstream correlate of VDR signaling and immune shifts; avoid presenting as a primary “direct inhibitor.” |
| 6 |
Wnt/β-catenin & EMT/invasion programs (reported) |
EMT / invasion pressure ↓ (reported; model-dependent) |
↔ |
G |
Anti-invasive phenotype |
Frequently discussed in colorectal and other models; keep “reported/model-dependent.” |
| 7 |
Angiogenesis signaling (VEGF outputs; reported) |
Angiogenic outputs ↓ (reported) |
↔ |
G |
Anti-angiogenic support |
Usually a later phenotype-level outcome tied to inflammatory and differentiation programs. |
| 8 |
Systemic endocrine axis: calcium/phosphate homeostasis |
Hypercalcemia risk if excessive (therapy-limiting for analogs) |
Bone/mineral homeostasis (core physiologic role) |
R, G |
Endocrine regulation |
Key reason active vitamin D analogs in oncology are constrained: dose-limiting hypercalcemia. |
| 9 |
Clinical oncology evidence (population-level) |
Incidence: generally no clear reduction; Mortality: some meta-analyses show modest reduction |
— |
— |
Translation constraint |
RCT meta-analyses often find reduced cancer mortality without clear reduction in total cancer incidence; results vary by trial design, baseline status, and dosing pattern. |
| 10 |
Safety / monitoring constraints (hypercalcemia; interactions) |
— |
Excess vitamin D can cause high calcium; risk increases with high-dose supplements and certain conditions/meds |
— |
Clinical risk management |
Upper limits and avoiding unnecessary high-dose regimens matter; routine testing is not recommended for most healthy people without indications. |
| Domain |
Normal BMI (<25) |
Overweight (25–29.9) |
Obesity (≥30) |
Interpretation / Notes |
| Baseline 25(OH)D Levels |
Higher on average |
Moderately lower |
Significantly lower (volume dilution + sequestration) |
Vitamin D is fat-soluble; adipose tissue can sequester vitamin D, lowering circulating 25(OH)D. |
| Response to Supplementation |
Greater increase per IU |
Blunted increase |
Markedly blunted increase |
Obese individuals often require higher doses to achieve the same serum 25(OH)D level. |
| VDR Expression / Signaling |
Baseline signaling intact |
Possible mild attenuation |
Evidence of altered vitamin D signaling (context-dependent) |
Obesity-associated inflammation and metabolic dysregulation may influence VDR activity. |
| Systemic Inflammation |
Lower baseline inflammatory tone |
Elevated |
Chronically elevated |
Obesity increases IL-6, TNF-α, CRP; this may blunt anti-inflammatory effects of vitamin D. |
| Cancer Incidence (VITAL Trial) |
No overall reduction in invasive cancer |
No significant reduction |
No significant reduction |
Primary endpoint showed no reduction across BMI groups. |
| Advanced / Metastatic Cancer Signal (Secondary Analyses) |
Stronger reduction signal in normal BMI |
Weaker effect |
No clear benefit observed |
Secondary analyses suggested benefit mainly in non-obese participants; interpretation remains debated. |
| Mortality Signal (Meta-analyses) |
Modest reduction reported |
Less consistent |
Attenuated or absent |
Some pooled analyses show reduced cancer mortality, with stronger signals in non-obese individuals. |
| Dose Considerations |
800–2000 IU/day often sufficient |
May require higher maintenance dose |
Higher supervised dosing sometimes required |
Guidelines emphasize individualized dosing based on measured 25(OH)D and clinical context. |
| Hypercalcemia Risk |
Low at standard doses |
Low–moderate (dose dependent) |
Still present at high doses |
Risk relates to absolute dose and duration, not BMI alone. |