Expression of survivin and clinical correlation in patients with breast cancer

Abstract

Survivin is a member of the inhibitor of apoptosis (IAP) family, which is also involved in the regulation of cell division and is also overexpressed and associated with parameters of poor prognosis in most human cancers, including carcinomas of the lung, breast, colon, stomach, esophagus and pancreas. This study examined the expression patterns of survivin in normal breast tissue, atypical hyperplasia, primary breast cancer and lymph node tissues involved in breast cancer and determined whether the expression of survivin is associated with the characteristics and prognosis of breast cancer. Formalin-fixed paraffin-embedded samples from 80 breast cancer, 20 atypical hyperplasia and 20 malignant lymph node tissue cases were immunostained using polyclonal survivin (Novus Biologicals, CO, USA). The degree of immunostaining was recorded on a scale of 0-3 according to the percentages of staining and distributions within the cytoplasm and nucleus. Survivin was expressed in 52, 14 and 17 of the 80 breast cancer (65%), atypical hyperplasia (70%) and breast cancer lymphoid (85%) specimens, respectively. Among those expressing cancer, 11.3%, 31.3% and 22.5% demonstrated only nuclear staining, only cytoplasmic staining and both nuclear and cytoplasmic staining, respectively. A statistical analysis revealed that cytoplasmic survivin expression was correlated with the stage, histological grade and L/N metastasis. In a Cox proportional hazard model analysis, the expression of survivin was not identified as a significant independent predictor of overall survival (P=0.168), although the decrease in the survival rate of survivin-positive patients did reach statistical significance (P=0.048). CONCLUSION: our results show that survivin is frequently overexpressed in primary breast cancer and its expression gradually increased from normal breast tissue to malignant lymph nodes. The expression of cytoplasmic survivin was common in breast cancer and could be both a useful diagnostic marker and an important source of prognostic information.