Fig. 6

Immunohistochemistry, expression of pathway-related proteins in undifferentiated mesenchymal cells (left) and cartilage (right) regions. Notch signaling (a, \(\:\times\:\)20) Negative for Notch1; (b,\(\:\times\:\)20) Positive for COL2A1 in the extracellular region, and high percentage of positive cells in the cartilage region; (c,\(\:\times\:\)20) Nuclear positive for SOX9. Wnt/β-Catenin (d,×20) Positive for WNT3A in the extracellular region; (e,×20) Nuclear and cytoplasmic positive for 𝛽-Catenin, and high percentage of positive cells in the undifferentiated mesenchymal round cell region; (f,×20) Nuclear and membrane positive for APC, and high percentage of positive cells in the undifferentiated mesenchymal round cell region. PI3K/AKT/mTOR (g,×20) Negative for PDGFRα; (h,×20) Nuclear, membrane, and cytoplasmic positive for AKT; (i,×20) Nuclear, membrane, and cytoplasmic positive for p-AKT, and high percentage of positive cells in the cartilage region; (j,×20) Nuclear and cytoplasmic positive for p-mTOR; (k,×20) Positive for GS, and cartilage cells are negative for GS; (l,×20) Membrane and cytoplasmic positive for PI3K; (m,×20) Nuclear, membrane, and cytoplasmic positive for PKC-𝛼; (n,×20) Membrane positive for CD99, and high percentage of positive cells in the undifferentiated mesenchymal round cell region; (o,×20) Nuclear positive for Bcl2, and high percentage of positive cells in the undifferentiated mesenchymal round cell region. TGF-β/BMP (p, ×20) Negative for TGF-β1; (q, ×20) Nuclear positive for SOX9; (r, ×40) Clear demonstration of positive expression of SOX9; (s, ×20) Nuclear and cytoplasmic positive for p-Smad2; (t, ×20) Positive for PAI-1 in the extracellular region; (u, ×20) Nuclear and cytoplasmic positive for p-Smad1. HES1 (v\(\:\times\:\)20) Nuclear positive for HES1