🔍 Overview
The PIK3CA gene encodes the p110α catalytic subunit of PI3K, a key player in the PI3K/AKT/mTOR signaling pathway, regulating:
- Cell growth
- Survival
- Metabolism
📊 Prevalence in Cancer
| Cancer Type | Mutation Frequency |
|---|---|
| Breast cancer | ~30–40% |
| Endometrial cancer | ~30–50% |
| Colorectal cancer | ~10–20% |
| Head and neck SCC | ~15–25% |
| NSCLC | ~5–10% |
| Bladder cancer | ~10–15% |
🔬 Hotspot mutations:
- E542K, E545K (helical domain)
- H1047R/L (kinase domain)
⚙️ Mechanism of Oncogenesis
- Mutations lead to constitutive PI3K activation, independent of receptor signaling.
- This causes:
- AKT activation
- mTOR pathway stimulation
- Increased proliferation and resistance to apoptosis