The simple idea (no memorising)
The cervix has two linings that meet at a border called the transformation zone — and that border is where nearly all cervical cancer begins. The cause is a virus, HPV (human papillomavirus):
Most HPV infections clear on their own. The danger is persistent infection with high‑risk types — especially HPV 16 and 18.
How the virus causes cancer
Two viral proteins switch off the cell's safety brakes:
- E6 disables p53 (a key "stop growth" guardian),
- E7 disables Rb (another growth brake).
With the brakes off, cells multiply out of control. A tell‑tale HPV footprint on a smear is the koilocyte — a cell with a clear halo around its nucleus.
The warning symptom
Early cervical cancer may be silent. The classic clue is bleeding after sex (postcoital bleeding), plus abnormal bleeding or discharge. (Memory hook: postcoital bleeding → think cervix.)
Pre‑cancer has two "languages"
- On a smear (cytology): LSIL and HSIL (low/high‑grade).
- On a biopsy (tissue): CIN 1, 2, 3.
Roughly, CIN 1 ≈ LSIL and CIN 2/3 ≈ HSIL. Don't mix a smear result up with a tissue diagnosis.
Why it matters
Because there's a known cause and a long pre‑cancer stage, cervical cancer can be stopped before it ever becomes cancer — which is exactly what the next concept is about.
Quick check ✅
- Which virus causes cervical cancer, and which two types are the highest‑risk?
- What do the viral proteins E6 and E7 switch off?
Remember this 🌟
Where we're going next → If we know the cause, we can prevent it. Concept 39.