Immunohistochemical evaluation of p53 and Ki-67 proteins in colorectal adenomas

Abstract

-Context -The appearance of adenomas and their progression to adenocarcinomas is the result of an accumulation of genetic changes in cells of the intestinal mucosa inherited or acquired during life. Several proteins have been studied in relation to the development and progression of colorectal cancer, including tumor protein p53 (p53) and antigen identified by monoclonal antibody . Objective -To evaluate the expression of p53 and Ki-67 in colorectal adenomas and correlate the observed levels with clinical and pathologic findings. Method -The sample consisted of 50 adenomatous polyps from patients undergoing colonoscopy. After performing polypectomy, polyps were preserved in a formalin solution with 10% (vol./vol.) phosphate buffer, submitted for routine preparation of sections and slides and stained with hematoxylin and eosin. For each adenoma we then performed immunohistochemistry to detect specific p53 and Ki-67 proteins using a streptavidin-biotin-peroxidase enzyme immunoassay.Results -p53 was detected in 18% of the adenomas. The average Ki-67 protein index (i.Ki-67) was 0.49. A statistically significant difference was observed in p53 (P = 0.0003) and Ki-67 (P = 0.02) expression between adenomas with low-and high-grade dysplasia, particularly for p53. The expression of Ki-67 was greater in rectal adenomas than in colic adenomas (P = 0.02). No relationship was found between the expression of the two proteins in the sample. Conclusion -The p53 protein is expressed in a proportion of adenomas, while the Ki-67 protein was expressed in all adenomas. The expression of p53 was higher in adenomas with high-grade dysplasia. The expression of Ki-67 was higher in rectal adenomas and in adenomas with high-grade dysplasia. HEADINGS -Colorectal neoplasm. Tumor suppressor protein p53. Ki67-antigen. Immunohistochemistry.

Ki-67 protein expression and tumor associated inflammatory cells (macrophages and mast cells) in canine colorectal carcinoma

“…Ki-67 index was strongly ( r  = 0.71; p  < 0.05) correlated with tumor malignancy. The results suggest association of Ki-67 with malignancy in canine CRC as was previously reported for human CRC [2, 15], prostate and breast cancers [14, 32] and various animal tumors [30, 33–35]. Because, there are genetic and pathogenic similarities between canine CRC and the human disease [36], in which Ki-67 prognostic value remained controversial [1, 14], its prognostic value in canine CRC is unknown at this time.…”

“…Ki-67 is widely applied in routine clinical work [9] and has been studied in relation to the development and progression of human CRC [2]. It was considered as an important predictive parameter in human CRC.…”

Efficacy and Safety of a Novel Submucosal Injection Solution for Resection of Gastrointestinal Lesions

“…TP53 encodes tumor protein p53, a long-established tumor suppressor protein. Although p53 expression may be downregulated in colonic cancer, increased expression has been documented in relation to the progression of colorectal adenomas [28] and with high-grade dysplasia in adenomas [29,30]. In turn, no changes were detected for PCNA, PTGS2 (COX2), CEACAM5 (carcinoembryonic antigen cell adhesion molecule 5), or MKI67 (marker of proliferation Ki67).…”

Analysis of Ki-67 expression as clinicopathological parameters in predicting the prognosis of adenoid cystic carcinoma

“…19 Nowadays, considerable research has been focussed on Ki-67 expression and malignant tumor prognosis. 20 In mammary tumors, Ki-67 expression has an independent and useful prognostic value in predicting recurrence, survival rate and therapeutic response. 10 For example, since Ki-67 expression increases in malignant oral tumors, it may be used as an indicator in predicting the prognosis of squamous cell carcinoma within the oral cavity.…”