In human cancers, the expression of many genes is amplified. Commonly amplified regions in breast cancer include 17q12, 8q24, and 11q13 which encode ERBB2 (164780), MYC (190080), and cyclin D1 (168461), respectively.

Guan et al. (1996) by using chromosome microdissection and hybrid selection cloned a target gene on 20q. This gene which is designated Amplified In Breast Cancer-1 or AIB1 is overexpressed in breast cancer. Two other amplified genes, designated AIB3 and AIB4 were also identified. In the August 15th, 1997 issue of Science Anzick et al. (1997) reported that AIB1 was ubiquitously expressed in normal human tissues and its expression was amplified in both breast and ovarian cancers. The deduced amino acid sequence of AIB1 consists of 1,420-amino acids and is a member of the SRC-1 family of nuclear receptor coactivators. This protein interacts with estrogen receptors (133430) in a ligand-dependent fashion, and functions to enhance estrogen-dependent transcription. Transfection of cells with AIB1 resulted in enhanced estrogen-dependent transcription suggesting that AIB1 is a nuclear receptor co-activator. It was suggested that the altered expression of this gene may contribute to the development of steroid hormone dependent cancers.

REFERENCE:

Anzick, S. L.; Kononen, J.; Walker, R. L.; Azorsa, D. O.; Tanner, M. M.; Guan, X.-Y.; Sauter, G.; Kallioniemi, O.-P.; Trent, J. M.; Meltzer, P. S. :

AIB1, a steroid receptor coactivator amplified in breast and ovarian cancer. Science 277: 965-968, 1997.
PubMed ID : 9252329

Guan, X.-Y.; Xu, J.; Anzick, S. L.; Zhang, H.; Trent, J. M.; Meltzer, P. S. :

Hybrid selection of transcribed sequences from microdissected DNA: isolation of genes within amplified region at 20q11-q13.2 in breast cancer. Cancer Res. 56: 3446-3450, 1996.
PubMed ID : 8758910