Immunohistochemical expression of Cyclin D1 in colorectal adenoma and adenocarcinoma , A comparative study.

Colorectal cancer is the most common gastrointestinal tract cancer worldwide. Cyclin D1 shows increased expression both in advanced adenomas , high dysplasia grade, and/or villous morphology) and colorectal adenocarcinoma with loss of expression in normal cells.Aim of study :To evaluate the IHC expression of Cyclin D1 in colorectal adenoma and compare it to adenocarcinoma and to correlate it with different parameters .Materials and methods:This retrospective study was done on tissue blocks of (40) cases (20) of which are colorectal adenomatous polyps,(20) were colorectal adenocarcinoma (covering the period from November 2018 to March 2020).Results:Cyclin D1 expression was lost in normal mucosa and showed variable staining, the adenoma staining percentage was score 0 in 20%(4), score I 20%(4) , score II 40%(8) and score III 20%(4) ,none had score IV While the staining percentage of colorectal adenocarcinoma was score 0 10%(2), score I 35%(7) , score II 35%(7), score III 5%(1) and score IV 15%(3) of cases.The mean immunohistochemical staining score was significantly higher in distal colorectal than proximal adenoma (p=0.045).When adenoma cases were evaluated separately for (histopathological type ,grade, size) 2 cases (10%) had villous adenoma morphology and 9 (45%) for tubular and tubulovillous ,11 (55%) showed high grade dysplasia and 9 (45%) showed low grade dysplasia and colorectal adenoma sizes ranged between (0.3-2.5) cm 15 (75%) were less than 2 cm ,5 (25%) were equal to or larger than 2 cm.The mean score showed a significant difference according to histopathological type (P value =0.11), grade of dysplasia (P value <0.001) and size ( P value =0.045)in colorectal adenoma.Conclusion: There was no significant difference in the Cyclin D1 score in colorectal adenoma and adenocarcinoma and showed a significant difference according to histopathological type , grade of dysplasia and size in colorectal adenoma.