Fig. 1. Different patterns of phagocytic activity of human tumor cells. (a) LAMP-1 staining of a human melanoma cell showing anapparently empty big vacuole, with two nuclei that are pushed to the periphery and with an apparent crescent shape; (b) LAMP-1 stainingof a human melanoma cell showing a vacuole containing two, apparently live, sibling cells; (c) Rab-5 staining of a human melanoma cellshowing various vacuoles containing cell or cell debris; (d) LAMP-1 staining of a human melanoma cell containing up to 18 ingested latexbeads. Immunophenotyping of fixed cells was performed using the PAP method. AEC was used as chromogen and Mayer’s hematoxylinfor the counterstaining. Magnification, 2500·.