Calretinin (CALB2) is a member of the EF-hand family of Ca(2+)-binding proteins and is expressed in a majority of poorly differentiated colon carcinoma and additionally in mesothelioma of the epithelioid and mixed type. Calretinin (CALB2) is a diagnostic marker for epithelioid mesothelioma. It is also a prognostic marker since patients with tumors expressing high calretinin levels have better overall survival. Silencing of calretinin decreases the viability of epithelioid mesothelioma cells. The calcium-binding protein calretinin (CALB2) is currently considered the most sensitive and specific marker for the diagnosis of malignant mesothelioma (MM). Calretinin (CALB2) is a diagnostic and prognostic marker in malignant pleural mesothelioma (MPM).