Employing antibodies against LGALS3 and lysosomal-associated membrane proteins 1 (LAMP1) or 2 (LAMP2), we have previously demonstrated that most of the MCF7 breast carcinoma and U2OS osteosarcoma cells growing in optimal culture conditions are, as expected, devoid of LGALS3-positive, leaky lysosomes39. Here, LGALS3 is linked to breast carcinoma.