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. It is also known as Latherin in horse, encoded by the Lath/Bpifa4 gene but is somewhat divergent from the other species. Latherin/BPIFA4 is a secreted protein found in saliva and sweat.
In humans, no functional protein is expressed, therefore BPIFB4P is referred to as a pseudogene. 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).
