Assessment of Immunohistochemical Expression of Molecular Markers: MMP-7, CD34, p53, bcl2, PCNA, Estrogen and Progesterone Receptors in Human Colorectal Tumors Using Computerized Image Analysis System. A Clinicopathological Study

Colorectal cancer (CRC) ranks the seventh among the commonest ten cancers in Iraq .It is a major public health problem and there is renewed interest in understanding the basic principles of its molecular biology. The development and progression of colonic carcinogenesis are known to be caused by the accumulation of cancer related genetic alterations, resulting in altered gene expression of oncogenes, tumor suppressor genes, and mismatch repair genes .These alterations affect the expression of a variety of downstream genes, including those involved in regulating the cell cycle, apoptosis, adhesion, and angiogenesis.
Aims of the study To evaluate the immunohistochemical expression of Matrix Metalloproteinase-7(MMP-7), CD-34, p53, bcl-2, Proliferating Cell Nuclear Antigen (PCNA), Estrogen and Progesterone receptors (ER and PR) in colorectal adenomas and adenocarcinomas using a computerized image analysis system (Digimizer) and to correlate this expression with different clinicopathological parameters of adenomas and carcinomas . Cases, Materials and Methods The study was retrospectively designed. A total of 86 tissue samples were included in the study.Out of the total number of tissue samples, 66 paraffin blocks from patients with colorectal tumors were collected from Gastroenterology and Hepatology Center, astroenterology unit at Al-Khadhmiya Teaching Hospital and private laboratories for the period 2006-2010, including 33 blocks from patients with colorectal adenoma and 33 blocks from patients with colorectal adenocarcinoma .The control group included 20 samples of apparently normal colonic tissue taken from autopsy cases from the Institute of Forensic Medicine .From each block, eight sections of 5µm thickness were taken, one section was stained with H&E and the other seven sections were immunohistochemically stained for MMP-7, CD-34, p53, bcl-2, PCNA, ER and PR. Results p53 expression was significantly higher in carcinoma than in adenoma (78.78% versus 36.36%,p-value<0.001) and it was significantly higher in adenomas with villous configuration, large size adenomas(≥1 cm), multiple lesions ,and those with severe dysplasia meanwhile it showed non-significant correlation with various clinicopathological parameters of colorectal carcinoma.bcl2 expression was significantly higher in adenoma in comparison with carcinoma (84.84% versus 48.48%, p-value<0.001). bcl2expression showed significantly higher levels in small sized adenoma (<1cm),solitary lesions,tubular adenomas and adenomas with mild dysplasia. There was a significant positive correlation between the expression of bcl2 and non-mucinous type of colorectal carcinoma and a negative correlation with size of the tumor. PCNA expression was significantly increased in a sequence of normal mucosa-adenoma-carcinoma.It was significantly higher in adenomas ≥1 cm and those with severe dysplasia and it showed a significant positive correlation with grade and lymph node involvement in colorectal carcinoma. The frequency of expression of ER and PR showed a gradual increase from control through adenoma to carcinoma. The frequencies of expression of ER in control, adenoma and carcinoma were (10%, 15.15% and 42.42% respectively, p-value <0.001) and those for PR were (10%, 24.24% and 36.36% respectively, p-value <0.001). There was no significant correlation of both receptors with clinicopathological parameters of adenoma and carcinoma.CD34 showed significantly higher expression in carcinoma than adenoma and in adenoma than control group. CD34 expression showed a significant correlation with adenomas carrying severe dysplasia and large sized adenomas (≥1cm) .It was significantly correlated with tumor grade,lymphovascular permeationand lymph node involvement in colorectal carcinoma. MMP-7 expression was significantly higher in carcinoma than adenoma (87.87% versus 45.45%, p-value<0.001). MMP7 expression showed a significant correlation with large sized adenomas (≥1cm), adenomas with villous configuration and those with severe dysplasia. There was a significant correlation between size, grade,stage, lymphovascular permeation and lymph node involvement in colorectal carcinoma and MMP-7 expression. Conclusions p53 overexpression is a late event in colorectal tumorigenesis and can be used as a marker of the risk of malignant transformation of advanced colorectal adenoma.bcl-2 may play an important role in the early stage of the adenoma-carcinoma sequence. PCNA expression is sequentially increased during neoplastic progression from normal colonic tissue into adenoma then carcinoma and plays an important role in colorectal carcinogenesis. ER and PR may play a role in colorectal carcinogenesis. Intratumoral quantification of CD34 expression in colorectal carcinoma reflects the grade of tumors and can predict lymph node involvement and lymphovascular permeation .MMP-7 plays an important role in the growth and malignant conversion of colorectal adenomas and might play an essential role in disease progression and lymph node metastasis of colorectal cancer. The use of Automated Cellular Image Analysis System yields more consistent assay results and improves assay objectivity and reproducibility