Immunohistochemical Expression of Cyclin D1 in Human Breast Carcinoma

Background: Breast cancer remains a major health problem in women. The molecular mechanisms of tumor growth and progression are complicated but likely involve the interaction of tumor suppressor genes. Oncogenes, cell cycle regulatory proteins and other factors. Recently some studies showed that Cyclin D1 is a cell cycle regulatory gene emerging as a potentially significant oncogene in invasive breast cancers. Objective: To evaluate immunohistochemical expression of cyclin D1 in women with breast cancer in our population and correlate its expression with different variables such as age, type of tumor and grade. Materials and methods: We retrospectively analyzed data from 76 formalin-fixed of paraffin-embedded tissues diagnosed with breast cancer which were collected from teaching laboratory unit in Baghdad medical city, Iraq, during the period from 2009 till 2013 and compared with positive control. These samples were investigated immunohistochemically, nuclear and cytoplasmic staining of tumor cells was accepted as positive. Results: The results showed that age distribution ranging from (28-67 years) with a mean age of 47.63 years. Regarding tumor types 68 (89.47%) cases were wit invasive ductal carcinoma, 6 (7.89%) cases were with invasive lobular carcinoma and 2 (2.63%) cases were recurrent carcinoma. Histologically the tumor grade ranges from well differentiated (grade 1) in 10 (13.15%) cases, moderately differentiated (grade 11) in 52 (68.42%) cases and poorly differentiated (grade 111) in 14 (18.42%) cases. Cyclin D1 expression was positive in 30 (39.47%) cases, while 46 (60%) cases negative. On the other hand most positive cases occurred within age group (41-55 years), invasive ductal carcinoma 26 (86.66%) and moderately differentiated 18 (60%) cases. significant differences noticed between IHC expressions of this marker with age, type of tumor and grade. Conclusion: cyclin D1 is an important regulator of cell cycle progression and overexpression of cyclin D1 has been linked to the development and progression of cancer, Cyclin D1 expression was seen more in invasive ductal carcinoma also is considered a novel and good marker of invasiveness in breast cancer tissue and may be used for treatment.