Figure 2: In a tumor cell, a mutation in the Bcl-2 gene results in increased expression will suppress the normal function of the pro-apoptotic proteins BAX and BAK, leading to malignancy [5]. On the other hand, a mutation in the BAX or BAK genes can cause a down-regulation of expression, causing the cell to lose the ability to regulate apoptosis, once again, leading to cancer cells. The inhibitor of apoptosis (IAP) family genes, which encode negative regulatory proteins, can prevent apoptotic cell death.