Associations between HER2 positive tumours and caspase-3 expression have not been reported previously; however, activation of HER2 can trigger downstream signalling via the phosphatidylinositol kinase 3 (PI3K/AKT) pathways, and AKT signalling has been shown to reduce the activity of caspase-9, the downstream effector of caspase-3 [37, 38]. Here, CASP9 is linked to neoplasm.