Abstract
Background/Aims
Serrated adenomas of the colon show mixed characteristics of both hyperplastic and adenomatous polyps. Serrated adenomas are known to progress via the serrated pathway than the adenoma-carcinoma pathway. The aim of this study was to evaluate the characteristics of traditional serrated adenomas compared to hyperplastic polyps and tubular adenomas by using immunohistochemical staining for p53, Bcl-2, and Ki-67.
Methods
Age, sex, location, size and the immunoexpression of p53, Bcl-2, and Ki-67 were retrospectively analyzed in 20 traditional serrated adenomas, 20 hyperplastic polyps, and 20 tubular adenomas from January 2007 to December 2012 at The Catholic University of Korea, Yeouido St. Mary's Hospital.
Results
There was no difference in Bcl-2 and p53 expression between traditional serrated adenomas and hyperplastic polyps. Ki-67 Expression of traditional serrated adenomas was higher than that of hyperplastic polyps (p=0.001). Ki-67 and p53 expression was similar between traditional serrated and tubular adenomas. Bcl-2 expression of traditional serrated adenomas was lower than that of tubular adenomas (p=0.001). Regarding the expression of p53, Bcl-2, and Ki-67 in traditional serrated adenomas, there were no statistical differences among age, sex, location, and size.
Conclusions
Our study suggested that Ki-67 may be helpful in distinguishing traditional serrated adenomas from hyperplastic polyps, and p53 expression may be ineffective in distinguishing between traditional serrated and tubular adenomas. From Bcl-2 expression, it is suggested that the tumorigenesis of traditional serrated adenomas is lower than that of tubular adenomas.
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![]() | Fig. 1.Immunohistochemical staining of p53 in traditional serrated adenoma, hyperplastic polyp, and tubular adenoma. Intense nuclear staining of p53 is seen in traditional serrated adenoma (A, ×200) and tubular adenoma (C, ×200). However, p53 protein overexpression is not observed in hyperplastic polyp (B, ×200). |
![]() | Fig. 2.Immunohistochemical staining of Bcl-2 in traditional serrated adenoma, hyperplastic polyp, and tubular adenoma. Traditional serrated adenoma (A, ×200) and hyperplastic polyp (B, ×200) show loss of Bcl-2 expression. Tubular adenoma (C, ×200) shows cytoplasmic immunoreactivity for Bcl-2. Small lymphocytes in the lamina propria are internal control of Bcl-2 immunostaining. |
![]() | Fig. 3.Immunohistochemical staining of Ki-67 in traditional serrated adenoma, hyperplastic polyp, and tubular adenoma. Ki-67 positive cells (brown color) are seen at the bottom and on the surface of individual crypts of traditional serrated adenoma (A, ×200), hyperplastic polyp (B, ×200), and tubular adenoma (C, ×200). |
![]() | Fig. 4.Receiver operating characteristic analysis of Ki-67 level to identify traditional serrated adenomas. Area under the curve (AUC) was 0.808 (95% CI, 0.672–0.943) with cutoff point of 6%. Sensitivity=65%, specificity=80%. |
Table 1.
Clinicopathologic Features of Patients with Traditional Serrated Adenomas, Tubular Adenomas, and Hyperplastic Polyps
Table 2.
Expressions of p53, Bcl-2, Ki-67 in Patients with Traditional Serrated Adenomas, Tubular Adenomas, and Hyperplastic Polyps
Table 3.
Relationship between Clinicopathological Features and Expressions of p53, Bcl-2, Ki-67 in Traditional Serrated Adenomas
Table 4.
Expressions of p53, Bcl-2, Ki-67 in Traditional Serrated Adenomas with Low and High Grade Dysplasia
Table 5.
Expressions of p53, Bcl-2, Ki-67 in Tubular Adenomas with Low and High Grade Dysplasia