Serpin B6 belongs to the serpin family. Serpin B6 localizes to the cytoplasm. Serpin B6 is expressed in many tissues, abundantly by mast cells in different tissues and mastocytoma lesions. Serpin B6 may be involved in the regulation of serine proteinases present in the brain or extravasated from the blood. In addition, Serpin B6 may play an important role in the inner ear in the protection against leakage of lysosomal content during stress and loss of this protection results in cell death and sensorineural hearing loss.