Expression Of P16 And P63 In Colonic Carcinoma And Precancerous Tissue

IntroductionColonic carcinoma is a familiar malignant tumor. The incidence rate and mortality rate is very high. Therefore, after colonic carcinoma diagnosis and right estimation of prognosis come true, adopting effective therapy have very important significance. However, there is no highly special and highly hypersensitive markers discovered for the moment. Many studies have shown that the pathological mechanism of colonic carcinoma is closely related to the activation of protooncogene or the inactivation of anti-oncogene. P16(Protein 16)is a kind of cyclinic control protein, which is the first discovered genetic protein restraining carcinoma occurrence by now. P63 gene is one of family members of P53, but unfamiliar with P53, P63 is not a standard anti-oncogene. P63 (Protein 63) can activate the activators regulated by P53 directly, leading cells to apoptosis. P63 mutation can seldom be found in human tumors and abnormal expression of P63 is a most frequently seen rather than P63 mutation in the tumors. Products of P63 have many kinds of isomers, which wave a complicated regulatory net with P53, forming a complex regulation mechanism on tumor formation.In this study, we performed immunohistochemical staining for P16 and P63 expression, discover the relations between which and colonic carcinoma and suggest the important significance that which can cue the occurrence of colonic carcinoma.MaterialFifty patients who had undergone surgical resections of colonic carcinoma were selected for our study. We examined sections from colonic carcinoma and precancerous tissue. The study cohort consisted of 26 men and 24 women (mean age 58 years, range 35～80years). The invasive depth of the cancerous tissue: 2 cases of mucosa, 13 cases of light muscle, 10 cases of deep muscle, 25 cases of chorion. Degree of differentiation: 24 cases of well differentiated degree, 17 cases of moderate differentiated degree, 9 cases of poorly differentiated degree. 27 cases of the section with lymph node metastasized, 23 cases of section without lymph node metastasized. Duke's stage: 2 cases of A stage; B stage: 12 cases of B1 stage, 9 cases of B2 stage; C stage: 11 cases of C1 stage, 15 cases of C2 stage; 1 case of D stage( liver metastasis).Main reagents:Anti-Human P16, Anti-Human P63, SP reagent box, AEC reagent box.Main instruments: Microscope(OLYMPUS BX40), refrigerator(Rong Sheng).MethodMethod:HE staining was performed for pathological diagnosis. The expression of P16,P63 was determined by SP immunohistochemical method. Statistic Analysis:SPSS11.0 statistic software was applied. All data were analyzed withχ2 test and p<0.05 was regarded as statistically significance. Results1. Expression of P16 and P63 in carcinoma and precancerous tissueThe positive rate of P16 expression in colonic carcinoma and precancerous tissue are 42% and 74%.There is significant difference between two groups compared (P<0.01). The positive rate of P63 expression in colonic carcinoma and precancerous tissue are 76% and 36%.There is significant difference between two groups compared(P<0.01). 2. The relation between P16 and P63 expression and Duke,s stageThe positive rate of P16 expression in colonic cancerous tissue of A+B stage is 56.5%, however the positive rate in colonic cancerous tissue of C+D stage is 29.6%. There is difference between two groups compared(P<0.05). The positive rate of P63 expression in colonic cancerous tissue of A+B stage is 22.2%, however the positive rate in colonic cancerous tissue of C+D stage is 52.2%. There is difference between two groups compared(P<0.05).3. The relation between P16 and P63 expression in colonic cancerous tissue and lymph node metastasisThe positive rate of P16 expression in colonic cancerous tissue with lymph node metastasis is 25.9%, however the positive rate in colonic cancerous tissue without lymph node metastasis is 60.9%. There is difference between two groups compared(P<0.05). The positive rate of P63 expression in colonic cancerous tissue with lymph node metastasis is 60.9%, however the positive rate in colonic cancerous tissue without lymph node metastasis is 22.2%. There is difference between two groups compared(P<0.05).4. The relation between P16 and P63 expression in colonic cancerous tissue and differentiated grade of colonic carcinomaThe positive rate of P16 expression in well differentiated colonic cancerous tissue is 41.7%, however the positive rate in moderate and poorly differentiated colonic cancerous tissue is 26.9%. There is difference between two groups compared(P<0.05). The positive rate of P63 expression in well differentiated colonic cancerous tissue is 18.2%, however the positive rate in moderate and poorly differentiated colonic cancerous tissue is 62.5%. There is difference between two groups compared(P<0.05). 5. The relation between P16 and P63 expression in colonic cancerous tissue and invasive depth of colonic cancerous tissueThe positive rate of P16 expression in invasive depth extending from mucosa to muscle is 60%, however the positive rate in invasive depth extending to chorion is 32%. There is difference between tow groups compared(P<0.05). The positive rate of P63 expression in invasive depth extending from mucosa to muscle is 24%, however the positive rate in invasive depth extending to serosa is 60%. There is difference between tow groups compared(P<0.05).6. Western Blot results of P63 proteinP63 protein expression in the cancerous tissue is higher than that in the precancerous tissue (P<0.05).7. Western Blot results of P16 protein P16 protein expression in the precancerous tissue is higher than that in the cancerous tissue (P<0.05).DiscussionP16 is the first discovered protein molecule which can inhibit many kinds of malignant tumors.P16 is not only the regular molecule for cyclin but also the key factor for inhibiting malignant tumor, which can combine with CDK4 protein competing with cyclin D1, inhibit the activity of CDK4 protein especially, can make the Rb protein in a hypo phosphorous station, inhibit cell multiplication, inhibit cellular growth. P63 gene is located in the 3q27-3q29 area of chromosome, containing two independent promotors. Study shows that P63 functions as the regulatory factor deactivating P53 and P53 can stabilize the P63. Hall et al found that P63 is expressed in all human tissues widely and selectively by immunohistochemical method. P63 is mainly dispersed in hyperplasia parts of epithelium such as oesophagus, oral mucous membrane, skin, and seminiferous tubule. Neck cells of gastric glands, basal cells of large intestine, glandular cell in lower 1/3 recess of small intestine have more positive cells of P63.This study examines 50 cases with the expression of P16, P63 in colonic carcinoma and precancerous tissue. The result shows that the low expression of P16 in colonic carcinoma tissue is quite different from the expression of precancerous mucosa. In the cancerous tissue, the higher Duke,s stage, the more lymph node metastasis, the lower differentiated of cancerous tissue, the deeper invasive depth of tissue, the positive rate of which is lower; The positive expression of P63 in colonic cancerous tissue is higher than that in precancerous tissue obviously; in the cancerous tissue, the higher Duke,s stage, the more lymph node metastasis, the lower differentiated of cancerous tissue, the deeper invasive depth of tissue, the positive rate of which is higher. Western Blot result shows that P63 is expressed highly in carcinoma tissues and the contents of P63 are different in differently differentiated tissues. The higher differentiation, the more P63 there is.Conclusion1,P16 commonly is expressed in nucleolus and cell plasma, expression rate of P16 in precancerous tissue is much mark higher than in cancerous tissue; with the higher Duke,s stage, the more lymph node metastasis, the lower differentiated stage of cancerous tissue, the deeper invasive depth of tissue, the positive rate of P16 expression is lower.2,P63 commonly is expressed in nucleolus, P63 is expressed in colonic precancerous tissue lower, however in colonic cancerous tissue which is expressed higher; with the higher Duke,s stage, the higher malignant degree, the lower differentiated stage of cancerous tissue, the deeper invasive depth of tissue, the positive rate of P63 expression is higher; Positive rate of P63 in colonic carcinoma with lymph node metastasis is higher than that without lymph node metastasis; P63 can be suggested as cancerous marker of colonic carcinoma.