FN1 and neoplasm: Third, blocking ITGAV, the common receptor of FN1 and SPP1, on tumor cells by peptide GRGDS or siRNAs abrogated the chemoattracting and anti-apoptosis activity of fibrotic lungs or fibrotic lung-derived fibroblasts and also attenuated the in vivo seeding and outgrowth of tumor cells in fibrotic lungs.