According to a new research, very small molecules that aid the cells in regulating which proteins they make in future, known as microRNAs, may lead doctors in predicting which liver-cancer patients may live longer than others.
For the study, the researchers compared levels microRNAs in tumor cells and adjacent nontumor cells from liver-cancer patients, a majority of whom also had hepatitis and cirrhosis.
It was discovered that patients with poor disease-free survival had low overall levels of 19 particular microRNAs, in comparison to those showing better survival after 16 years of follow-up.
The study was led by Thomas D. Schmittgen, associate professor of pharmacy and a researcher with Ohio State's Comprehensive Cancer Center.
"The findings must be verified in larger groups of patients, but they suggest that we might improve survival in some liver-cancer cases by adding back those microRNAs as a drug," said Schmittgen.
However, he added that this possibility would require years of additional laboratory and preclinical research.
Liver cancer, also known as hepatocellular carcinoma, is the third most common cause of cancer death worldwide, killing some 662,000 people in 2005, according to the World Health Organization (WHO). This disease is more prevalent in men and is usually caused by hepatitis infection or cirrhosis of the liver.
In the study, the researchers examined specimens from 43 liver tumors, of which 28 were paired with nearby nontumor tissue, and specimens from six normal livers. Also, two-thirds of the cancerous livers had hepatitis and cirrhosis.
They also observed the levels of 196 different microRNAs in liver-cancer cells as against nearby noncancer cells, and in liver cells with hepatitis and cirrhosis as against healthy cells.
According to these two comparisons, interesting differences in microRNA levels came out. However, the most important finding came when the researchers looked for a relationship between cancer-cell microRNA levels and disease-free survival times in 25 patients for whom disease-free survival data was available.
After the analysis it was shown that generally patients with poor survival had lower levels of 19 particular microRNAs than did patients with significantly better survival.
"This may also be a good clue as to which microRNAs are most important in liver cancer," said Schmittgen.
The study is published in a recent issue of the journal Clinical Cancer Research.