Estrogen receptor alpha gene amplification in breast cancer: 25 years of debate

Figure 1 Prevalence of estrogen receptor alpha gene amplification in the literature. The fraction of altered cases (y-axis) is indicated across published studies (x-axis) and is shown separately for different detection methods. The studies are sorted in descending order of ESR1 amplification frequency, as detected. A: Prevalence of ESR1 amplification defined according to the diagnostic criteria for ERBB2 (HER2) amplification; B: Prevalence of ESR1 copy number increase including amplification and gain. For study citations see Appendices A-D. ESR1: Estrogen receptor alpha gene; MLPA: Multiplex ligation-dependent probe amplification; FISH: Fluorescence in situ hybridization; CISH: Chromogenic in situ hybridization.