Prognostic importance of survivin in breast cancer

Abstract

Survivin is a member of the inhibitor of apoptosis (IAP) family, and is also involved in the regulation of cell division. Survivin is widely expressed in foetal tissues and in human cancers, but generally not in normal adult tissue. This study examined the expression of surviving protein in a series of 293 cases of invasive primary breast carcinoma. Survivin immunoreactivity was assessed using two different polyclonal antibodies, and evaluated semiquantitatively according to the percentage of cells demonstrating distinct nuclear and/or diffuse cytoplasmic staining. Overall, 60% of tumours were positive for survivin: 31% demonstrated nuclear staining only, 13% cytoplasmic only, and 16% of tumour cells demonstrated both nuclear and cytoplasmic staining. Statistical analysis revealed that survivin expression was independent of patient's age, tumour size, histological grade, nodal status, and oestrogen receptor status. In multivariate analysis, nuclear survivin expression was a significant independent prognostic indicator of favourable outcome both in relapse-free and overall survival (P<0.001 and P=0.01, respectively). In conclusion, our results show that survivin is frequently overexpressed in primary breast cancer. Nuclear expression is most common and is an independent prognostic indicator of good prognosis.

Figure 1

Infiltrating tumour cells showing (A) distinct nuclear positivity with polyclonal antibody to survivin (× 200 magnification) and (B) both nuclear and cytoplasmic positivity with antisurvivin antibody (× 400 magnification).

Figure 2

Kaplan–Meier estimates for (A) disease-free survival and (B) overall survival, by nuclear survivin <20 vs ⩾20%, adjusted for cytoplasmic result, oestrogen receptor status, lymph node status, grade, and size.