PDGFRB and idiopathic pulmonary fibrosis: Several oxindole-based multikinase inhibitors (Figure 2) have been approved for cancer treatment such as sunitinib (2006) for gastrointestinal stromal tumour and renal cell carcinoma as PDGFR and VEGFR inhibitor79, and nintedanib (2014) for idiopathic pulmonary fibrosis as FGFR, PDGFR and VEGFR inhibitor.80