INPP4B and breast cancer: To investigate the mechanism by which high expression of annexin A1 contributes to poor TNBC prognosis, we studied endogenous expression of several breast cancer-relevant pathways, including the PI3K pathway, since TNBC have high levels of PI3K/AKT pathway activity resulting from a number of alterations including PI3KCA mutations and loss of PTEN and INPP4B [23].