MLH1 and cancer: Of 43 MSI-H cancers, 14 failed to express the MLH1, seven failed to express MSH2, while 22 expressed MLH1 and MSH2. Of 32 MSI-L/MSS cancers, 28 expressed MLH1 and MSH2, three failed to express MLH1 and one failed to express MSH2. Five MSI-H cancers failed to express the MSH6, of which one failed to express MLH1, three failed to express MSH2 and only one cancer failed to express MSH6 alone (Table 3).