In addition, we noted that the endogenous SS18 or SS18-SSX1 shows as a similar puncta-like distribution in mouse embryonic stem or synovial sarcoma cells as that of overexpression in HeLa, HEK293T, or synovial sarcoma cells30,32 (Figs. 3–5). This evidence concerns the gene SSX1 and synovial sarcoma.