Fig. 2.

MMR protein expression corresponds to TML in GBM. MMR protein expression was determined by IHC in GBM cases (n = 30). Only 6.7% (2 of 30) demonstrated loss of MLH1 (A), 10% (3 of 30) loss of MSH2 (B), 13.3% (4 of 30) loss of MSH6 (C), and 6.7% (2 of 30) loss of PMS2 (D). When these GBM cases were analyzed for TML, 6 showed high TML. Of the GBMs with high TML, at least 1 MMR enzyme was found to have defective expression (E). High TML was defined as more than 20 mutations per 1.4 Mb, moderate TML as 11–20 mutations per 1.4 Mb, and low TML as 10 or fewer mutations per 1.4 Mb. ns = not significant.