WTP8.13 Expression of Integrin Subunit Alpha 7 (ITGA7) predicts survival from breast cancer following adjuvant chemotherapy

Abstract

Abstract Aim To investigate the relevance of ITGA7 expression with respect to clinical prognostic markers, disease-free survival (DFS) and disease-specific survival (DSS) after adjuvant chemotherapy in breast cancer. Methods Breast cancer tissue was obtained from a tissue microarray comprising all tumour subtypes in 305 women. Expression of ITGA7 was determined by immunohistochemistry. Relative expression of ITGA7 was assessed. Results Overall, it was concluded that ITGA7 levels were independent of the clinical prognostic markers, tumour grade, lymph node status, oestrogen receptor status and molecular subtype. Kaplan-Meier survival analyses showed, high ITGA7 nuclear protein expression was associated with longer DFS, mean 647 days; p=0.036 in the whole cohort. The same trend was visible for ITGA7 cytoplasmic protein expression albeit that this was not significant. Sub-analysis of ER-positive breast cancers also showed that high ITGA7 nuclear protein expression was associated with both a longer DFS and DSS, 682 days, p=0.05 and 604 days, p=0.005 respectively. Kaplan-Meier survival analysis was performed separately on the patients who received either taxanes with anthracyclines or anthracyclines without taxanes. This demonstrated a significant increase in DFS, 806 days; p=0.004 in primary breast cancers that had high ITGA7 nuclear protein expression in the group that received anthracycline-based chemotherapy alone. No statistically significant difference in DFS or DSS was noted between high and low ITGA7 expression in the group that received anthracycline and taxane based adjuvant chemotherapy. Conclusion ITGA7 has been identified as impacting upon DFS and DSS in breast cancer potentially via the modification of chemoresponse.