Abstract: The present invention generally provides compositions methods and composition relating to the diagnosis and/or treatment of cancers having a cell surface de-N-acetylated sialic acid antigen, e.g., an at least partially de-N-acetylated ganglioside and/or a de-N-acetylated sialic acid-modified cell surface protein.

Abstract: Disclosed herein are brown algae-derived fucoidan and in particular a method for degrading fucoidan to a low-molecular weight so that fucoidan as sparingly-degradable polysaccharide (M.W. 3,000,000 to 5,000,000) can be more efficiently extracted from brown algae and it can be absorbed in the human body. The method comprises preparing a fucoidan extract containing as much fucoidan as possible from brown algae selected from Hizikia fusiforme, Undaria pinnatifida, Laminaria saccharina, Ecklonia cava, Cladosiphon Okamuranus and Nemacystus decipiens, and low-molecularizating the fucoidan extract using Vibrio halioticoli (Accession No. KCTC 10998BP) and a probiotic mixture containing Streptococcus faecalis, Bacillus mesentericus, Clostridium butyricum, and glycosyltransferase thereof. According to the method, fucoidan can be efficiently degraded to a low molecular weight using microorganisms so that it can be absorbed in the human body.