GPC1 and neoplasm: Advanced T classification (p = 0.007), T3-T4 grouping (p = 0.001; Figure 4), positive NG2/CSPG4 transcript expression (p = 0.029; Figure 4), or GPC1 positivity in stromal cells (p = 0.007) were all conditions strongly associated with a high loco-regional tumour relapse rate (Table 3).