The transactivation activity of the different AP-2α isoforms was further tested on the ERBB2 promoter, which is known to possess two functional AP-2 binding sites, mapping at -210 and -500 upstream of the transcription start site, which are required for positive regulation of ERBB2 by AP-2α in breast tumour lines [22,27]. The gene discussed is ERBB2; the disease is breast neoplasm.