Amplified in breast cancer 1 expression in breast cancer.
OBJECTIVE
The amplified in breast cancer 1 (AIB1), steroid receptor co-activator family member, acts as an oestrogen receptor (ER) co-activator. Acting with HER-2, it is thought to play a role in endocrine resistance by facilitating ER-growth factor crosstalk. The aim was to analyse AIB1 expression by immunohistochemistry and study its correlations with other prognostic variables in breast cancer and its effect on survival.


METHODS
A tissue microarray comprising tumours from 438 patients with 15.4 years' median follow-up was used. Interpretable AIB1 expression obtained in 395 patients was analysed along with other prognostic factors in breast cancer.


RESULTS
AIB1 expression scores ranged from 0 to 30; positive AIB1 expression (score > 14) was seen in 146/395 breast cancers; it correlated negatively with ER (P = 0.003) and progesterone receptor (PR) (P = 0.007), and positively with HER-2 (P = 0.005) and tumour grade (P = 0.014). It did not correlate with nodal status (P = 0.437). Among ER+ patients, AIB1 expression showed a trend towards loss of PR expression (29% versus 20%; P = 0.14). AIB1 did not predict survival on univariate or multivariate analysis.


CONCLUSIONS
AIB1 expression correlates with HER-2 expression in breast cancer and shows a trend of association with loss of PR expression in ER+ tumours. Our study supports the postulated role of AIB1 in ER-growth factor interactions.
Thorat
M A
MA
Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
Turbin
D
D
Morimiya
A
A
Leung
S
S
Zhang
Q
Q
Jeng
M-H
MH
Huntsman
D G
DG
Nakshatri
H
H
Badve
S
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D051548:Histone Acetyltransferases / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D056921:Nuclear Receptor Coactivator 3; D016019:Survival Analysis; D015534:Trans-Activators / Q000378:metabolism*
D015534:Trans-Activators; D051548:Histone Acetyltransferases; C538866:NCOA3 protein, human; D056921:Nuclear Receptor Coactivator 3