TGFB1 and cancer: Utilization of the MCF10A and MDA-MB-231 cell lines have led to a deeper understanding of the five W’s of cancer metastasis including what the extracellular matrix is [5]; when growth factor (e.g., TGFβ) signaling is unfavorable for tumorigenesis yet pro-metastatic [8,9]; how metastatic cells remodel distant organs [10,11]; and, finally, the debatable conclusion of why faster cancer cell migration is an indicator of metastatic potential [12,13,14,15].