48 h after transfection, we found that SYF2 siRNAs (SYF2-si-SYF2#1, SYF2-si-SYF2#2, SYF2-si-SYF2#3) could knock down the endogenous SYF2 compared to the negative control, and SYF2-si-SYF2#3 significantly inhibited the expression of SYF2 in breast cancer cells (Figure 5A and 5C; Figure 5B and 5D). This evidence concerns the gene SYF2 and breast cancer.