In addition, HSP decreases Bcl-2, mitochondrial AIF, mitochondrial Apaf-1, and mitochondrial cyt-c, which drive cancer cell apoptosis, while upregulating a few intracellular ROS, ATP, Ca2+, and cytosolic components such as AIF, Apaf-1, cyt-c, caspase-3, caspase-9, and Bax [156]. This evidence concerns the gene CASP9 and hereditary spastic paraplegia.