Background: Colorectal adenocarcinoma is the most common type of gastrointestinal cancer, with about 150,000 cases each year in the United States and about 56,730 deaths from colorectal cancer risk. In Iraq and according to the Iraqi cancer registry (ICR) reports, the incidence of colorectal carcinoma was 4.55% of whole body malignancy, & it is the seventh cause of death from cancer (ICR 2005). In males, it’s the 7th common cancer while in females it’s the 4th most common cancer. The estrogen and progesterone receptors belong to a super- family of nuclear hormone receptors. These receptor proteins function as transcription factors when they are bound to their respective ligands, these receptors shares a common structural and functional organization

Objectives: to evaluate the immunohistochemical expression of estrogen (ER) and progesterone (PR) in colorectal adenocarcinoma and to correlate this expression with different clinical and pathological parameters.

Material and method: Twenty five cases of colorectal adenocarcinoma diagnosed in private laboratories in Baghdad/Iraq from November 2011 to march 2013, were respectively evaluated in term of age, gender, pathological diagnosis, including the tumor site, size, lymph nodes status, grade and stage of tumor. Using infiltrative ductal carcinoma of the breast as control for both estrogen and progesterone receptors expression were investigated immunohistochemically, nuclear and cytoplasmic staining of tumor cells were accepted positive.

Results: Fourteen (56%) of the cases were male, 11 (44%) case were female, with age distribution ranging from (24-84) years, with a mean age of 56.5 year. Tumor size ranges between 2.5-10 cm, mean of 6.25 cm. Seven cases (28%) cases were from the caecum, 5(20%) from each rectum, sigmoid and left colon respectively and 3(12%) cases were from more than one segment of the colon. Histologically the tumor grade ranges from moderately differentiated in 23(92%) cases and poorly differentiated in 2(8%) cases. Regarding pathological staging (TNM system), 5(20%) cases were stage T2, 17 (68%) cases were stage T3 and 3(12%) cases were T4, lymph node involvement found in 10(40%)  cases and distant metastasis were found in 2 (12%) cases. Estrogen receptors expression was positive in 2(8%) cases, while progesterone receptor was positive in 5(20%) cases; both ER positive cases were PR positive. Both ER positive cases were female; one of the PR positive cases was male. All of the ER and PR positive cases were moderately differentiated, one case of ER positive tumor showed nodal involvement while three cases of PR positive showed nodal involvement.      

Conclusion: - Estrogen and progesterone receptors in colorectal adenocarcinoma had same activity. The level of ER and PR expression in tumor tissue could not predict malignant biological behavior of the colorectal adenocarcinoma. No significant statistical correlation was observed between ER, PR expression and any of the studied clincopathological parameters.