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The Korean Journal of Pathology 2005;39(4): 222-228.
An Analysis of p53, bcl-2 and Ki-67 Expressions, and Apoptosis in Rectal Cancer: Their Correlation with the Tumor Response after Preoperative Radiochemotherapy.
Jinyoung Yoo, Su Zy Kim, Hyeon Min Cho, Sung Whan Kim, Hyung Min Chin, Jung Yong Lee, Jun Ki Kim, Seok Jin Kang, Chung Soo Chun, Chang Suk Kang
1Departments of Pathology, The Catholic University of Korea College of Medicine, Seoul 442-723, Korea. sjkang@vincent.cuk.ac.kr
2Departments of Radiation Oncology, The Catholic University of Korea College of Medicine, Seoul 442-723, Korea.
3Departments of Surgery, The Catholic University of Korea College of Medicine, Seoul 442-723, Korea. sjkang@vincent.cuk.ac.kr
ABSTRACT
Background : Preoperative radiochemotherapy (RCT) has been administered for locally advanced rectal cancer to increase the therapeutic benefits, and to preserve the sphincter in low-lying tumors, however, tumor responses after RCT are variable. Methods : Apoptotic index (AI), and expressions of Ki-67, p53 and bcl-2 were analyzed in pretreatment biopsies from 69 patients with rectal cancer by immunohistochemistry. Tumor response was graded in surgically resected specimens by using a three-scale grading system: no response (NR), partial remission (PR) and complete remission (CR). Results : CR was identified in 19 cases (28%), PR in 24 cases (35%), and NR in 26 cases (38%) of 69 cases. p53 protein was expressed in 49 cases (71%), whereas bcl-2 was in 42 cases (61%). The pretreatment Ki-67 labeling index was 65.4+/-3.4%. The tumor response was not associated with any of these markers. Tumors with CR/PR showed a higher AI (0.84+/-.84%/0.66+/-.52%) than that of tumors with NR (0.58+/-0.54%). There was a significant correlation between tumor response and the histologic differentiation (p=0.008) or recurrence (p=0.039). Conclusions : The AI revealed a tendency to increase in tumors with CR/PR, while expressions of p53 and bcl-2, and Ki-67 labeling index had little direct association with tumor response.
Key Words: Rectal neoplasms; Protein, p53; bcl-2 protein antigen; Ki-67 protein antigen; Apoptosis