TAIPEI: Tri-Service General Hospital yesterday unveiled a new cervical cancer screening method that it says has achieved an accuracy of 99 percent. The screen looks for a chemical change called DNA methylation in cervical tissues.

According to obstetrician and gynecologist Lai Hung-cheng, the method involves the identification of four tumor-suppressor genes in the cervical tissues - SOX1, PAX1, LMX1A and NKX6-1 - and measures their altered methylation patterns.

Tumor-suppressor genes normally protect cells from becoming cancerous, but the gradual silencing of these genes by abnormal methylation is considered an early sign in cancer development.

Lai said an analysis of tissue specimens using the new method, which takes only two working days to complete, can diagnose 99 percent of carcinomas in the cervical area.

The new method also allows women to collect the specimens themselves, thus avoiding the embarrassment of having it done by a doctor, Lai said.

He said the method is obviously better than pap smear screening, which can produce false negative results and has an accuracy rate of only 60 percent to 70 percent.

It is also an improvement on tests that look for human papillomavirus (HPV) infections, because there are many types of HPV and not every type can lead to cancer, Lai said, adding that he has applied for a patent for the new method in several countries.

China Daily/CNA

(HK Edition 05/08/2009 page1)