PDGFRB and pulmonary fibrosis: We examined the level of PDGFR-β in MWCNT-induced lung fibrosis and demonstrated that MWCNTs (XNRI MWNT-7, 40 μg) remarkably increased the PDGFR-β expression and the number of PDGFR-β positive cells in mouse lungs on day 7 post-exposure, especially in interstitial fibrotic foci1.