BACKGROUND: Hepatocellular carcinoma has a poor prognosis because
of the high intrahepatic recurrence rate. There are technological
limitations to traditional methods such as TNM staging for accurate
prediction of recurrence, suggesting that new techniques are needed.
METHODS: We investigated mRNA expression profiles in tissue specimens
from a training set, comprising 33 patients with hepatocellular
carcinoma, with high-density oligonucleotide microarrays representing
about 6000 genes. We used this training set in a supervised learning
manner to construct a predictive system, consisting of 12 genes,
with the Fisher linear classifier. We then compared the predictive
performance of our system with that of a predictive system with
a support vector machine (SVM-based system) on a blinded set of
samples from 27 newly enrolled patients. FINDINGS: Early intrahepatic
recurrence within 1 year after curative surgery occurred in 12
(36%) and eight (30%) patients in the training and blinded sets,
respectively. Our system correctly predicted early intrahepatic
recurrence or non-recurrence in 25 (93%) of 27 samples in the
blinded set and had a positive predictive value of 88% and a negative
predictive value of 95%. By contrast, the SVM-based system predicted
early intrahepatic recurrence or non-recurrence correctly in only
16 (60%) individuals in the blinded set, and the result yielded
a positive predictive value of only 38% and a negative predictive
value of 79%. INTERPRETATION: Our system predicted early intrahepatic
recurrence or non-recurrence for patients with hepatocellular
carcinoma much more accurately than the SVM-based system, suggesting
that our system could serve as a new method for characterising
the metastatic potential of hepatocellular carcinoma.