Objective: Data on Hormone Receptor and Her-2/neu expression in breast cancers from Saudi Arabia and Gulf Region is sparse. We undertook this study to describe the patterns of hormone receptor and Her-2/neu protein expression in breast carcinoma and compared them with the histological grade at a University Hospital in Riyadh.

Material and Method: We conducted a retrospective study on 164 invasive ductal carcinoma of breast between the year 2002 and 2008. Immunohistochemical analysis for Estrogen and Progesterone Receptor and Her-2/neu was done in all the cases. Fluorescent in situ hybridization for Her-2/neu gene amplification was performed in all 2+ cases and few equivocal 1+ and 3+cases by immunohistochemistry. Correlation between Estrogen and Progesterone Receptor and Her-2/ neu amplification and grade of tumor was calculated.

Results: The expression of Estrogen Receptor, Progesterone Receptor were significantly correlated (p<0.001). Also, there was a significant negative correlation between expression of hormone receptor and Her-2/neu amplification. The histologic grade of the tumor was significantly correlated to the expression of both Estrogen and Progesterone Receptor. However, the relationship between Her-2/ neu amplification and grade was not significant and many of the grade III tumor were Her-2/neu negative. In addition, Her-2/neu gene amplification by fluorescent in situ hybridization was observed in 84.6% of breast cancer that were 3+ and in 18.75 % cases that were 2+ by immunohistochemistry.

Conclusion: Prevalence of Estrogen and Progesterone Receptor expression and Her-2/neu amplification in breast cancer in the Saudi Arabian population is similar to that reported internationally. There is a negative correlation between hormone receptors expression and Her-2/neu amplification. However not all of the high-grade breast cancers showed Her-2/neu positive status.