CanAssist Breast (CAB) is a validated proteomic-based prognostic test performed on BC samples that predicts the risk of distant recurrence within 5 years of diagnosis for patients with hormone receptor-positive, Her2-negative early BC. CAB uses the immunohistochemistry (IHC) technique to assess the expression of five protein biomarkers (CD44, ABCC4, ABCC11, N-cadherin, and pan-cadherin) on formalin-fixed paraffin-embedded (FFPE) surgically resected tumor tissues. Here, ABCC4 is linked to breast cancer.