Tiny molecules that help cells regulate which proteins they make might one day help doctors predict which liver-cancer patients are likely to live longer than others. Researchers compared levels of microRNA in tumor cells and adjacent nontumor cells from liver-cancer patients, most of whom also had hepatitis and cirrhosis. Patients with poor disease-free survival had low overall levels of 19 particular microRNAs compared with those showing better survival after 16 years of follow-up.