A Novel Method of Reporting c-erbB-2 Overexpression; Correlation With Grade but not With Other Prognostic Parameters in Breast Cancer

Authors: MUSTAFA SAMUR, ŞEYDA KARAVELİ, HAKAN BOZCUK, ELİF PESTERELİ, MUSTAFA ÖZDOĞAN, MUSTAFA YILDIZ, MEHMET ARTAÇ, BURHAN SAVAŞ

Abstract: Overexpression of erbB-2 protein is a marker of clinically aggressive behavior in breast cancer patients. In general erbB-2 status is reported on a scale from negative to 3+, depending on staining intensity, if more than 10% of the tumor cells are stained. However, the original definition does not take into account the percentage of stained cells in detail, since all samples score in the same way if they are above the cut-off, established at 10%. In this study, we evaluated the erB-B2 overexpression by immunohistochemistry in 169 patients and evaluated any correlation with the other well known prognostic parameters. We also tested whether there was a difference between the original definition of c-erbB-2 positivity (2+ or 3+) and a novel system, the total c-erbB-2 score, which takes into account both the percentage, and intensity of staining as a continuous variable. The total c-erbB-2 score was correlated with the grade (P = 0.006) but not with other parameters. When 2+ and 3+ levels of staining together were regarded as positive, a similar correlation with grade was demonstrated. However, when only 3+ cases were considered, there was no significant correlation. In conclusion reporting c-erbB-2 as a continuous variable may make more sense than treating a cut-off value as positive.

Keywords: c-erbB-2, HER-2/neu, breast cancer, grade

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