TSPAN8 and familial pancreatic carcinoma: For this reason, a cooperative role for integrins and tetraspanins in targeting exosomes to selected tissues has been suggested; tetraspanins, in fact, have been found in exosomes derived from different cancer cell types, and exosomes released from a rat pancreatic cancer cell line transfected with tetraspanin-8 (Tspan8) and β4 integrin were found to preferentially bind to spleen cells, and lung and kidney tissues [30].