NTRK1 and neoplasm: When in soluble form, decorin inhibits tumor growth by downregulating several receptor tyrosine kinases (RTKs) [30] such as the EGFR [31]–[34], IGF-IR [35]–[38], and Met [39]–[41] primarily by evoking caveolin-mediated internalization and degradation [31], [39], [42].