Researchers discovered a blood screening technique that could
make it possible to detect early-stage hepatocellular carcinoma
(HCC) and predict how well a patient will do following
treatment. Scientists previously knew that the DNA of HCC tumor
cells lack a functioning copy of RASSF1A, due to
hypermethylation. Methylation-specific PCR, however, destroys
about 85–93% of the DNA in a blood sample. Together with the
fact that tumoral DNA is only present at very low concentrations
in blood during early stages of HCC, this method has not been
sensitive enough to detect altered RASSF1A in blood, reports
K.C. Allen Chan, a professor at the Chinese University of Hong
Kong. To compensate, Chan and his colleagues invented a new
technique that they call methylation-sensitive enzyme-mediated
real-time PCR. This combines real-time PCR with an enzyme that
breaks unmethylated DNA apart. With this new method, Chan’s team
was able to separate out the altered methylated DNA. To test the
relationship between altered RASSF1A and