| IntroductionColonic carcinoma is a familiar malignant tumor. The incidence rate and mortalityrate is very high. Therefore, after colonic carcinoma diagnosis and right estimation ofprognosis come true, adopting effective therapy have very important significance.However, there is no highly special and highly hypersensitive markers discovered forthe moment. P16 (Protein 16) is a kind of cyclinic control protein, which is the firstdiscovered genetic protein restraining carcinoma occurrence by now. CDK4 (CyclinDependent Kinase 4) is a kind of cyclinic protein dependent kinase. The contents andactivated degree can limit the speed of cell multiplication period from G stage to Sstage, accordingly which participate in regulation of cell period. Most study has shownthat P16 and CDK4 have close relation with malignant tumor occurrence. In this study,we performed immunohistochemical staining for P16 and CDK4 expression, discoverthe relations between which and colonic carcinoma and suggest the importantsignificance that which can cue the occurrence of colonic carcinoma.MaterialFifty patients who had undergone surgical resections of colonic carcinoma wereselected for our study. We examined sections from colonic carcinoma and precanceroustissue. The study cohort consisted of 26 men and 24 women (mean age 58 years, range35(?)80years). The invasive depth of the cancerous tissue: 2 cases of mucosa, 13 casesof 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 nodemetastasized, 23 cases of section without lymph node metastasized. Duke's stage: 2cases of A stage; B stage: 12 cases of B stage, 9 cases of B stage; C stage: 11 cases ofC stage, 15 cases of C stage; 1 case of D stage( liver metastasis).Main reagents: Anti-Human P16, Anti-Human CDK4, SP reagent box, AECreagent box.Main instruments: Microscope (OLYMPUS BX40) , refrigerator (Rong Sheng).MethodMethod: HE staining was performed for pathological diagnosis. The expression ofP16,CDK4 was determined by SP immunohistochemical method.Statistic Analysis: SPSS11．0 statistic software was applied. All data were analyzedwith x test and p<0．05 was regarded as statistically significance.Results1,Expression of P16,CDK4 in carcinoma and precancerous tissueThe positive rate of P16 expression in colonic carcinoma and precancerous tissueare 42% and 74%.There is significant difference between two groups compared(p<0．01) . The positive rate of CDK4 expression in colonic carcinoma and precanceroustissue are 68% and 36%.There is significant difference between two groups compared(P<0．01) .2,The relation between the P16,CDK4 expression and Duke' s stageThe positive rate of P16 expression in colonic cancerous tissue of A+B stage is56．5%, 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 ofCDK4 expression in colonic cancerous tissue of A+B stage is 52．2%, however thepositive rate in colonic cancerous tissue of C+D stage is 81．5%. There is differencebetween two groups compared (P<0．05) .3,The relation between the P16,CDK4 expression in colonic cancerous tissue and lymph node metastasisThe positive rate of P16 expression in colonic cancerous tissue with lymph nodemetastasis is 25．9%, however the positive rate in colonic cancerous tissue withoutlymph node metastasis is 60．9%. There is difference between two groups compared (P<0．05) . The positive rate of CDK4 expression in colonic cancerous tissue with lymphnode metastasis is 74．1%, however the positive rate in colonic cancerous tissue withoutlymph node metastasis is 52．2%.There is difference between two groups compared (P<0．05) .4,The relation between the P16,CDK4 expression in coloniccancerous tissue and differentiated grade of colonic carcinomaThe positive rate of P16 expression in well differentiated colonic cancerous tissueis 41．7%, however the positive rate in moderate and poorly differentiated coloniccancerous tissue is 26．9%. There is difference between two groups compared(P<0．05) .The positive rate of CDK4 expression in well differentiated colonic cancerous tissue is54．2%, however the positive rate in moderate and poorly differentiated coloniccancerous tissue is 80．8%. There is difference between two groups compared (P<0．05) .5,The relation between the P16,CDk4 expression in coloniccancerous tissue and invasive depth of colonic cancerous tissueThe positive rate of P16 expression in invasive depth extending from mucosa tomuscle 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 ofCDK4 expression in invasive depth extending from mucosa to muscle is 52%, howeverthe positive rate in invasive depth extending to chorion is 84%. There is differencebetween tow groups compared (P<0．05) . DiscussionP16 is the first discovered protein molecule which can inhibit many kinds ofmalignant tumors.P16 is not only the regular molecule for cyclin but also the key factorfor inhibiting malignant tumor, which can combine with CDK4 protein competing withcyclin D1, inhibit the activity of CDK4 protein especially, can make the Rb protein in ahypo phosphorous station, inhibit cell multiplication, inhibit cellular growth.CDK4 is aimportant regular molecule in G1 stage of cellular period. CDK4 can combine withcyclin Dl to form complex specially, complex (CDK4/cyclin D1) can make remnantgroup of serine and threonine in Rb protein phosphor-trate. Commonly Rb protein in ahypo-phosphorus station, and combine with transfer factor E2F induce cyclin E toexpress. The complex formed by cyclin E and CDK2 can also make Rb proteinphosphor-trate, accordingly induce more E2F to release, form a positive feedback. Atthe same time, released E2F can also stimulate self gene transferring, accordingly forma positive feedback also, Due to these two positive feedback, the activity of E2F andcyclin E promote rapidly at the cross point of G1-S,induce of a serious of targetmolecule expression related to G1-S transformation and advance of stage, impel cellaccomplishing DNA copy. This study examine 50 cases with the expression of P16,CDK4 in colonic carcinoma and precancerous tissue. The result shows that the lowexpression of P16 in colonic carcinoma tissue is quite different from the expression ofprecancerous mucosa. In the cancerous tissue, the higher Duke' s stage, the more lymphnode metastasis, the lower differentiated of cancerous tissue, the deeper invasive depthof tissue, the positive rate of which is lower; The positive expression of CDK4 incolonic cancerous tissue is higher than in precancerous tissue obviously; in thecancerous tissue, the higher Duke' s stage, the more lymph node metastasis, the lowerdifferentiated of cancerous tissue, the deeper invasive depth of tissue, the positive rateof which is higher. Conclusion1,P16 commonly is expressed in nucleolus and cell plasma, expression rate ofP16 in precancerous tissue is much mark higher than in cancerous tissue; with thehigher Duke' s stage, the more lymph node metastasis, the lower differentiated stage ofcancerous tissue, the deeper invasive depth of tissue, the positive rate of P16 expressionis lower.2,CDK4 commonly is expressed in nucleolus, CDK4 is expressed in colonicprecancerous tissue lower, however in colonic cancerous tissue which is expressedhigher; with the higher Duke' s stage, the higher malignant degree, the lowerdifferentiated stage of cancerous tissue, the deeper invasive depth of tissue, the positiverate of CDK4 expression is higher; Positive rate of CDK4 in colonic carcinoma withlymph node metastasis is higher than which without lymph node metastasis; CDK4 canbe suggested as cancerous marker of colonic carcinoma.
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