It recognizes a protein of about 29kDa, which is identified as Calretinin (also known as Calbindin 2). Calretinin is a vitamin D-dependent calcium-binding protein involved in calcium signaling. It is present in subsets of neurons throughout the brain and spinal chord, including sensory ganglia. Antibody to calretinin is useful in differentiating mesothelioma from adenocarcinomas of the lung. It also aids in differentiating adrenal cortical neoplasms from pheochromocytomas.