The mouse microarray consistently detected the four human csecretase subunits overexpressed in the S-1 cell line (Table 1) . By applying a cut-off based on the false discovery rate (FDR, i.e., the probability to wrongly accept a difference between the two conditions) with a p value of 0.005, we found 2658 EST clones (1981 genes) to be differentially expressed, with 1241 EST clones of increased and 1417 EST clones of decreased transcription upon enhanced c-secretase activity (Supplemental Material, Dataset S1 and Dataset S2).