BPI fold containing family A, member 4 (BPIFA4) is a non-human protein encoded by the Bpifa4 gene in mammals such as monkey, cat, and cow but does not appear in rodents and humans.[3][4] It is also known as Latherin in horse, encoded by the Lath/Bpifa4 gene but is somewhat divergent from the other species.[5][6][7] Latherin/BPIFA4 is a secreted protein found in saliva and sweat.
In humans, no functional protein expressed therefore BPIFB4P is referred to as a pseudogene.[7][8][9] However, a non-functional protein does appear; it known as BASE protein, secreted by breast cancer cell lines and salivary gland tissue (see section below).[10][11]
