Calretinin is a calcium-binding protein related to calmodulin and calbindin. It is found in neuron groups in the cortex, retina and spinal cord. It is known that calretinin is produced in the tumor cells of a mesothelioma.
In normal skin, calretinin is expressed in the inner cell layer of the outer root sheath of the harfollicle and in eccrine and apocrine sweat glands. Furthermore, the excretory duct and the gland of the sebaceous follicle express calretinin.