MAPT and Alzheimer disease: We also conducted an in-vitro 3H-MK-6240 binding assay, 3H-MK-6240 autoradiography, p-tau immunohistochemistry, and X-34 stain in the same frozen blocks of cortical tissue from six autopsy cases with neuropathological diagnosis of CTE Stage III (of IV) and Braak NFT Stage III (of VI) but no Aβ pathology by CERAD criteria and from a typical AD case with Braak Stage VI.