Patients with FL fall into 2 major groups with respect to outcome. The subset of patients (approximately 80%) who progress at least 24 months after initial therapy (non-POD24) have a favorable outcome and near-normal life expectancy. The 20% of patients who progress within 24 months (POD24) have an unfavorable prognosis, in part because of the presence of histologic transformation at relapse. Presently, there is no reliable way to identify these 2 groups at diagnosis or target specific therapies to one group or the other.