The granular cytoplasmic SPOCK1 reaction raised the possibility that the proteoglycan localizes in the mitochondria; thus, double fluorescent immunostainings were carried out with SPOCK1 antibody together either with TOMM20 or mitochondrial marker (MitoTracker-red, M22425) on hepatoma cell lines (Figure 6). Here, TOMM20 is linked to hepatocellular carcinoma.