Abstract
Immunostaining for cyclin D1 has become essential for the reliable diagnosis of mantle cell lymphoma (MCL). MCL is associated with a poor prognosis and its distinction from other small B‐cell lymphomas is clinically important. However, many diagnostic laboratories report problems in finding a reliable method. The following articles by Chan and by Miller, Munson & Isaacson discuss the common problems and describe successful methods with advice on diagnostic interpretation.