SACK1A and cancer: Though initially this may seem to contradict our hypothesis that FAM83A is critical to the earliest phases of BC initiation, and less so to cancer local progression and invasion, we propose at least two explanations for FAM83A’s resurgent expression in advanced disease: [1] FAM83A’s involvement in treatment resistance [6]; and [2], as observed in other tumor types [10], FAM83A’s role in the late phase of breast tumorigenesis, potentially metastatic disease, which has not been investigated here.