Elevated expression of AP-1 activity in human breast tumors as compared to normal adjacent tissue

The levels of AP-1 activity in human breast lesions and in adjacent normal tissue were studied by a gel retardation assay. A thirty nucleotide long consensus oligonucleotide to the adenovirus E3 gene AP-1 sequence (E3AP-1) was end labelled and reacted with nuclear extracts from breast lesions and adjacent normal tissue. A total of 20 tissue extracts (8 pairs of tumor and normal tissue from the same patient and 4 tumors) were examined. All 12 tumor tissues showed elevated levels of AP-1 as compared to the 8 normal tissues. These results suggest that the AP-1 transcription factor may play a role in breast neoplasia.