BECN1 and neoplasm: The essential autophagy gene beclin 1 (BECN1) is a haploinsufficient tumor suppressor (Liang et al., 1999, Qu et al., 2003, Yue et al., 2003) that is also located on the breast cancer tumor susceptibility chromosomal locus 17q21, ~ 150 kb centromeric to BRCA1 (Aita et al., 1999).