Expression Of The Regulation Factors CyclinD1, P27 And P16 Of Cell Cycle In The Colorectal Carcinoma

Background and Objective: The cell cycle is the basic process of living cell. Its regulation depends on three-dimensional network regulating system composed of cyclins, cyclin dependent kinases (CDKs)and cyclin dependent kinases inhibitors(CKIs). The abnormal expression of any component in this system can cause malignant proliferation. CyclinD1 is the most important member in the cyclin family, it can promote the cell to get into S period from G period by combining with CDK4 and CDK6 to form compound. It is a positive regulation factor of the cell cycle. Both p27 and p16 are important members in the CKIs family. By combing with CDKs or cyclin-CDKs, p27 inhibits the activity of CDKs, which further controls the change of the cell cycle G1/S. It is a negative control factor of the cell cycle. P16 mainly competes with cyclinD1 to combine with CDK4/CDK6, and then put off the cell to get into S period from the G1 period. It is also an important negative control factor of the cell cycle. By analyzing the protein expression of cyclinD1,p27 and p16 in the colorectal carcinoma and their relation with clinicopathological parameters , this project investigated the role of the three factors in the genesis and progress of the colorectal carcinoma.Methods: 53 cases of colorectal carcinoma tissues were obtained by surgical excision and proved by the pathology, while 30 cases of normal large intestine tissues obtained by endoscope biopsy as normal control. Immunohistochemistry one-step method was used to examine the expression of protein cyclinD1, p27 and p16 respectively in all tissues. According to clinical stage ( Dukes stage ) and differentiated degree of carcinoma ,carcinoma cases were divided into different groups and the expression of cyclinD1, p27,p16 in each group were compared byχ2 test .Results: 1. The positive expression rate of cyclinD1 is 64.15% in the colorectal carcinoma tissues and 6.67% in the normal tissues ( p<0.01 ) . The positive expression rate of p27 is 30.19% in the colorectal carcinoma tissues and 76.67% in the normai tissues ( p<0.01 ) . The positive expression rate of p16 is 43.39% in the olorectal carcinoma tissues and 83.33% in the normai tissues ( p<0.01 ).2. In the well differectiated carcinoma, moderately differectiated carcinoma and poor differectiated carcinoma, the positive expression rate is 53.33%, 54.55%, 87.50% respectively for cyclinD1; 53.33%, 31.82%, 6.25% respectively for p27;66.67%, 45.45%, 18.75% respectively for p16; Compared moderately and well differectiated carcinoma with poor differectiated carcinoma, each of these three indicators has significant difference ( p<0.05 ).3. Compared with A+B stage and C+D stage in Dukes stage of colorectal carcinoma, the positive expression rate is 48%,78.57% for cyclinD1 ( p<0.05 ) ; 44%, 17.86% for p27 ( p<0.05 ) , and 64%,25% for p16 ( p<0.05 ). Conclusions: 1. There is a higher expression for cyclinD1 and lower expression for p27 and p16 in colorectal carcinoma , indicating that these changes are related to the occurrence of colorectal carcinoma .2. The poorer the differectiated degree of colorectal carcinoma, the higher expression of cyclinD1 protein , while the lower expression of p27 protein and p16 protein . They are related to the malignant degree of colorectal carcinoma, indicating that they can be taken as the important indicators in evaluating the malignancy degree of colorectal carcinoma.3. It has relationships with the clinical stage of the colorectal carcinoma for the higher expression of cyclinD1 protein and lower expression of p17 protein and p16 protein, which can provide an important reference to the clinical biology manifestation and prognosis of the patients suffering from colorectal carcinoma .This research investigated the roles of the regulation factors cyclinD1, p27 and p16 of cell cycle in the occurrence of the colorectal carcinoma and their relation with the clinical biology manifestation, indicating that the examination of the three factors can be taken as important indicators for diagnosis and evaluation of the malignancy degree of colorectal carcinoma. It also revealed that the occurrence and development of colorectal carcinoma is dueto the coordinated work of many genes, and a joint test will help the accurate evaluation in the diagnosis and prognosis.