Expression And Significance Of β-catenin And APC Protein In Endometrial Adenocarcinoma

Objective: To study the expression and role ofβ-catenin and APC (Adenomatous polyposis coli) protein in endometrial adenocarcinoma.Method: The endometrial tissue from 60 cases of endometrial adenocarcinoma which were further defined according to the operative findings (FIGO 2000) as stage I(32 cases), stage II (12 cases) and stage III-IV(16 cases) and graded as high grade (G1 22 cases) and moderate grade (G2/G3 38 cases),20 cases of endometrial hypertrophy which were subdivided (according to the WHO Scully et al. suggestions-1994 )as simple hypertrophy(8 cases), complex hypertrophy(17 cases) and atypical hypertrophy(5 cases) and 30 cases of normal endometrial tissue of which 15 samples were from proliferate phase of menstrual cycle and 15 samples from secretory phase of menstrual cycle, were collected from patients at the People's Hospital of TaiXing from August 2004 to December 2007. The expression ofβ-catenin and APC protein was detected using immunohistochemistry.Results:1. There was obvious decrease in the positive expression rate ofβ-catenin in endometrial adenocarcinoma (36.67%, 22/60) compared to endometrial hypertrophy (70.00%, 14/20) and normal endometrial tissue (63.33%, 19/30), (P<0.05); the nuclear expression was seen in endometrial adenocarcinoma and endometrial hypertrophy, the rate of expression was (30.00%, 18/60) (60.00%,12/20) respectively, but the nuclear expression in normal endometrium was zero (P<0.05).2. There was statistically significant increase in the expression rate ofβ-catenin in stage I of endometrial adenocarcinoma compared to stage II, III and IV (P<0.05, P<0.0001 respectively). There was no statistically significant difference between stage II and stage III-IV (P>0.05). There was statistically significant difference in theβ-catenin expression between high grade (G1) (54.55%, 12/22) compared to the moderate grade disease (G2/G3) (26.32%, 10/38) (P<0.05).3. APC protein was mainly located on the nucleus. The positive expression rate in endometrial adenocarcinoma, endometrial hypertrophy and normal endometrial tissue was (50.00%, 30/60), (45.00%, 9/20) and (63.33%, 19/30) respectively (P>0.05).Conclusion:1.There was obvious decrease in the positive expression rate ofβ-catenin in endometrial adenocarcinoma compared to endometrial hypertrophy and normal endometrial tissue. Also, the expression ofβ-catenin was higher in stage I compared to stage II, III and IV and higher in high grade (G1) compared to the moderate grade (G2/G3) disease.The nuclear expression ofβ-catenin was seen in endometrial hypertrophy and endometrial adenocarcinoma cases but not in the normal endometrial glandular cells. These findings suggest that the changes in theβ-catenin gene play an important role in the progression and development of early endometrial carcinoma.2.APC protein was mainly located on the nucleus.There was no statistically significant difference in the expression rate between endometrial adenocarcinoma, endometrial hypertrophy and normal endometrial tissue. These suggest that APC protein may not have a significant role in the pathogenesis of endometrial adenocarcinoma.