Rabbit anti Human FAP alpha antibody detects fibroblast activation protein alpha (FAP alpha), a type II membrane protein belonging to the serine protease family. FAP alpha is upregulated on activated fibroblasts in response to wounding, and may also be involved in epithelial-mesenchymal interactions during development and tissue repair. Active FAP alpha is a ~170 kDa homodimeric protein which can also exist as a soluble form. FAP alpha can also form heterodimeric complexes with CD26 (DPP4), and these proteins may function co-ordinately to modulate the growth, differentiation, adhesion and metastasis of tumour cells.