BECN1 and cancer: Instead, in human MCF7 breast carcinoma cells, enforced expression of Beclin 1 inhibited the tumor-forming potential of this cell line [64]; therefore, Beclin 1 is an effector of the autophagic pathway (Figure 4), and we may speculate that autophagy is involved in tumorigenesis repression; however, it should be said that the Beclin 1 gene is not specifically mutated or deleted in cancer, but rather, it is lost because of chromosome 17q21 deletions [65].