FUCA1 and breast cancer: In the present study, we demonstrated that the lysosomal enzyme, α-L-fucosidase 1 (FUCA1, EC number 3.2.1.51) that catalyzes the hydrolytic cleavage of terminal fucose residues was preferentially detected in early-stage (stage 0 to 2) breast cancer tissues (n = 236, *P = 0.015 and 0.024, respectively).