Although the surface GD3 levels on the two cell models we targeted for GD3S-KO were relatively modest (Supplementary Fig. S6 and S7), further immunological targeting of GD2 and/or GD2S deletion should elucidate the functional role of GD2 versus GD3 in PC tumorigenesis. The gene discussed is ST8SIA1; the disease is pachyonychia congenita.