Background and objective: Survivin is a novel member of the inhibitor of apoptosis (IAP) gene family. It is associated with more aggressive behavior and parameters of poor prognosis in most human cancers including gastric, colorectal and bladder carcinomas. However, conflicting data exist on its prognostic effect in breast cancer. This current study is designed to assess survivin expression in breast carcinoma relating results with clinicopathological parameters, proliferation (MIB-1) and molecular classification
Material and methods: Our retrospective study comprised of 65 archived cases of breast carcinoma. Samples from the tumor and the adjacent normal breast tissue were immunostained for survivin and MIB-1. Nuclear and cytoplasmic survivin expression was evaluated in normal breast tissue and carcinoma regarding both the intensity and the percentage of positive cells. ER, PR, HER2 were used as surrogate markers to classify the cases into four molecular subtypes.
Results: Survivin expression was detected in 78.5% of breast carcinomas. The adjacent normal breast tissue was immunonegative. Survivin expression showed significant association with increased tumor size (p<0.0001), high histologic grade (p=0.04), lymph node metastases (p<0.001), advanced tumor stage (p<0.0001), MIB-1 expression (p=0.02), negative estrogen receptor status (p=0.01) and negative progesterone receptor status (p<0.0001). The subcellular localization of survivin significantly related to histologic grade, stage and lymph node involvement. The percentage of TNP (triple negative phenotype) and HER2+/ER-PR- tumors expressing survivin were significantly higher compared to the Luminal subtypes (p=0.01).
Conclusion: Survivin expression was associated with parameters of poor prognosis in breast cancer. Moreover, the cancer-specific expression of survivin, coupled with its importance in inhibiting cell death and in regulating cell division, makes it a potential target for novel cancer treatment.
Key words: Breast carcinoma - Immunohistochemistry - MIB-1 - Molecular classification - Survivin.