Estrogen receptor alpha/beta, AIB1, and TIF2 in colorectal carcinogenesis: do coregulators have prognostic significance?
OBJECTIVE
Estrogen receptor beta (ER beta) is abundantly expressed in colorectal tissue, but its role in colorectal carcinogenesis remains elusive. Estrogen receptor coregulators, amplified in breast cancer 1 (AIB1) and transcription intermediary factor 2 (TIF2), have been well-characterized, but their expression in colorectal carcinomas has not been investigated.


METHODS
Estrogen receptor alpha (ER alpha), ER beta, AIB1, and TIF2 protein expression were evaluated by immunohistochemistry in colorectal normal mucosa, adenomas, and adenocarcinomas from 110 patients with colorectal cancer.


RESULTS
ER alpha expression was rare in colorectal tissue and its expression does not appear to be associated with colorectal carcinogenesis. ER beta, AIB1, and TIF2 were detected in the nucleus of epithelial, endothelial, inflammatory, smooth muscle cells, and myofibroblasts. The expression of the three proteins was significantly increased in epithelial cells of carcinomas compared to normal mucosa. In carcinomas, a significant correlation between the levels of expression of AIB1 and TIF2 was noted. Although AIB1 overexpression was associated with local tumor invasion, it was also found to correlate independently with prolonged overall survival.


CONCLUSIONS
ER beta, AIB1, and TIF2 appear to be involved in colorectal tumorigenesis and might have prognostic significance.
Grivas
Petros D
PD
Division of Oncology and Clinical Oncology Laboratory, Medical School, University of Patras, 26504, Patras, Greece.
Tzelepi
Vassiliki
V
Sotiropoulou-Bonikou
Georgia
G
Kefalopoulou
Zinovia
Z
Papavassiliou
Athanasios G
AG
Kalofonos
Haralabos
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000378:metabolism*; D047628:Estrogen Receptor alpha / Q000378:metabolism*; D047629:Estrogen Receptor beta / Q000378:metabolism*; D005260:Female; D051548:Histone Acetyltransferases / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000473:pathology; D008297:Male; D008875:Middle Aged; D051958:Nuclear Receptor Coactivator 2 / Q000378:metabolism*; D056921:Nuclear Receptor Coactivator 3; D010166:Palliative Care; D011379:Prognosis; D016019:Survival Analysis; D015534:Trans-Activators / Q000378:metabolism*
D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D051958:Nuclear Receptor Coactivator 2; D015534:Trans-Activators; D051548:Histone Acetyltransferases; C538866:NCOA3 protein, human; D056921:Nuclear Receptor Coactivator 3