ESR2 and cancer: In addition, a study by Kefalopoulou et al. showed that the expression of ERβ coactivators, such as AIB1 (nuclear receptor coactivator 3 amplified in breast 1), TIF2 (nuclear receptor coactivator 2), and PELP1 (proline-, glutamic acid-, and leucine-rich protein 1), are involved in the initiation, progression, and metastatic potential in various types of cancer [68].