FN1 and neoplasm: OncFN is a marker of the tumour vasculature7 and a principal component of the metastatic microenvironment, termed the premetastatic niche, in many tumours.8 Multivariate analysis showed that overexpression of OncFN was associated with a trend towards significantly lower overall survival rates.9 Although the role of FN1 in tumours has been explained, the intracellular metabolism of FN1 and its mechanism are not sufficiently understood.