BECN1 and breast carcinoma: To test this hypothesis, we independently overexpressed N-terminally His6-tagged Bag-1S (His6Bag-1S), Bag-1L (His6Bag-1L), and Beclin 1 (His6Beclin 1) proteins in MDA-MB-231, MCF-7, and BT-474 human breast cancer cell lines since they exhibit differences in their prognosis to the disease progression due to their origin and the rates of survival and recurrence.