Hassanain H Khudier* & Daria Ismail Ameen@*MB,ChB, FIBMS Path., Department of Pathology, College of Medicine, University ofSulaimania. @MB,ChB, Pathology lab., gynecological and obstetric SulaimaniaTeaching Hospital.Correspondence to: Dr. Hassanain H. Khudair, Sulaimania teaching hospital, E-mail: hhk1970@gmail.comAbstractColorectal cancer regarded as one of the most widespread malignant tumor in the world.It is considered the second leading death factor among people in some developedcountries. Colorectal cancer comprises several distinct histological types includingadenocarcinoma which forms 85%-95% of all colorectal cancer cases. Pathogenesis ofcolorectal cancer is a multistep process characterized by involvement of many geneticalterations, including p53.The aim of this study is to detect the expression of p53 protein in colorectal carcinomaand to show its relationship with some clinicopathological features including age,gender, histological types, histological grades and staging.Forty paraffin-embedded tissue blocks of colectomy specimens were used in thisretrospective study. They were collected from the Department of Pathology in SulaimaniaTeaching Hospital, Shorsh Hospital and Shehid Saifeddin Private Clinic from January2007 to July 2008.Two sections of 4 micrometer thickness were taken from each paraffin embedded tissueblock. First section was taken for hematoxylin and eosin stain and the other one forimmunohistochemistry [anti-p53 monoclonal antibody] by using DakoCytomationEnvision + Dual Link System-HRP (DAB+). The relationship between p53 over expressionand the dependent variable (age, gender, histological types, histological grades, andstaging) were evaluated statistically using an analysis of variance (ANOVA) with STATA 8soft ware (College station, Tx). A positive reaction for p53 was scored on a semiquantitativebase as score 0 (no staining), score 1+ (weak staining), score 2+ (moderatestaining), and score 3+ (strong staining).Staining was negative for p53 (score 0) in 16 cases (40%). Positive cases were scored as(1+) in 4 cases (10.0%); (2+) in 8 cases (20.0%); and (3+), in 12 cases (30.0%). There wereno significant relationships between p53 over expression and age (p=0.682), gender(p=0.924), histological types (p=0.30), histological grades (p=0.516), and the stage of thedisease (p=0.281). Conclusions: Considering the p53 protein over expression in arelatively high percentage of patients, it seems that p53 mutation may play an importantrole in the development of colorectal carcinoma. There were no significant relationshipsbetween p53 protein expression and some clinicopathologic variables such as age,gender, histological types, histological grades, and the stage of the disease.