Complex sentence: Most cases of CIN stay the same or are eliminated by the host's immune system without intervention, but a small percentage of cases progress to become cervical cancer, usually cervical squamous cell carcinoma, or SCC.
Split into simpler sentences: Most cases of CIN remain stable, or are eliminated by the host's immune system without intervention. However a small percentage of cases progress to become cervical cancer, usually cervical squamous cell carcinoma, or SCC.