Bacterial sialidases serve parasitic nutritional functions for several pathogens and may act directly as virulence factors in some diseases e.g. cholera, gas gangrene, septiacemia, meningitis and cystic fibrosis [24], trypanosomal sialidases are crucial for the life-cycles of the parasitic species causing sleeping sickness and Chagas disease [25,26], human Neu3 sialidase is a potential target for cancer treatment [27], Neu1, Neu3 and Neu4 may find use in cancer diagnosis [28] and mutations in Neu1 are the cause of the lysosomal storage disease sialidosis [29]. Here, NEU4 is linked to cancer.