63P - Expression of cohesin subunit SA2 predicts breast cancer survival

Date 07 May 2015
Event IMPAKT 2015
Session Welcome reception and Poster Walk
Topics Breast Cancer
Translational Research
Presenter Heli Repo
Citation Annals of Oncology (2015) 26 (suppl_3): 15-24. 10.1093/annonc/mdv117
Authors H. Repo
  • Pathology, University of Turku, 20520 - Turku/FI

Abstract

Body

Introduction: Cohesin is one of the the main regulators of sister chromatid separation during the metaphase/anaphase transition. It is a multiprotein complex consisting of four core subunits, one of those being the SA2 subunit. The SA2 subunit plays the final critical role in dismantling the cohesion complex from the sister chromatids. It also has roles in DNA double-strand break repair and gene regulation. There is increasing evidence on the involvement of both over- and underexpression of cohesin in several types of malignancies. Here we present the analysis of cohesin subunit SA2 immunohistochemical expression in a large breast cancer patient material.

Material and methods: The study was based on a material of 445 breast cancer patients with a maximum of 22 years follow up. SA2 immunohistochemistry was performed on tissue microarrays of breast cancer tissue. The intensity of SA2 staining was classified low or high compared to normal breast tissue expression. DNA content was determined by image cytometry on cell imprints.

Results: In our results, low SA2 immunohistochemical expression was associated with less favorable prognosis for breast cancer patients. Low expression of SA2 predicted a 1.6-fold risk of breast cancer death (p = 0.0208). The majority of patients (75%) with low SA2 expression were dead within 6.0 years of diagnosis whereas high SA2 expression predicted an average of 17.6 years of survival. No statistically significant association could be detected between SA2 immunoexpression and DNA aneuploidy.

Conclusion: Our results and previous literature indicate that decreased SA2 immunoexpression predicts unfavorable course of breast cancer without association to aneuploidy or specific mutations.

Disclosure: All authors have declared no conflicts of interest.