As a first step to address such isoforms in pediatric sarcomas, we re-examined whole cell protein lysates of cell lines at a higher separation and in comparison to characterized RON isoforms (Figure 5a): HT-29 cells express the 180 kDa (kilodalton) wild-type pro-RON precursor, which is cleaved into the 40 kDa α-chain and the 150 kDa wild-type RON β-chain [18]. This evidence concerns the gene MST1R and sarcoma.