GPT and glioblastoma: The seven C-Circle positive cases, were mostly positive for PML foci, co-localized with TRF2 (Figure 4d, upper panel; see Table 1); some were negative for TERT (three out of seven, Figure 4d, green highlight in Table 1) suggesting that ALT is the main TMM active in these tumors; three C-Circle/PML positive tumors, including one juvenile GBM and two GBM/PNC were also positive for TERT expression (pink highlight in Table 1).