By immunofluorescence, the nuclear STAT3 level was decreased in the neurons of brain slice of AD patients, where phosphorylated tau at pS202 and pT205 (AT8) was shown high immunoreaction (Figure 1K), with the ratio of pY705 STAT3/total STAT3 increased while the total STAT3 in the cortex of AD patients had no significant change (Figure 1I-J). This evidence concerns the gene STAT3 and Alzheimer disease.