FN1 and neoplasm: In contrast, the use of a Fibronectin polyclonal antibody allows us to stain for any type and physical state of Fibronectin fibers.[34, 51, 52, 56] This enabled us for the first time, to map the tensional state of Fibronectin fibers in tissue cryosections from healthy mice organs and induced cancer models.[51, 56, 57] In these mouse tumor models, we previously discovered unexpectedly that large fractions of Fibronectin fibers are untensed.