BECN1 and breast cancer: This was also confirmed in co-immuno-precipitation experiments where endogenous FYVE-CENT R1945Q mutant protein extracted from HCC-1954 breast cancer cells and Beclin 1 did not co-immuno-precipitate with an antibody against endogenous FYVE-CENT, whereas wild-type FYVE-CENT from a control cancer cell line was able to co-immuno-precipitate with Beclin 1 (Figure 2D).