We also proved the existence of fucose in the outer chains of PSA from cancer cells (Figs. 5b,c and 8), and significant expression of α1,3 FTs (Supplementary Fig. S1) in CTOS and 22Rv1, which regulate the synthesis of Lex and SLex in PC-3 prostate cancer cell22. The gene discussed is FUT4; the disease is cancer.