Myosin-IIA S1943 phosphorylation as a marker of tumor invasion

A method for determining if cells of a tumor in an organ or in a tissue in a subject, are likely to invade another organ or tissue in the subject comprising determining if a sample of the tumor, or a sample obtained from the tumor, comprises human myosin-IIA heavy chain phosphorylated at residue S1943, comprising contacting the sample of the tumor, or the sample obtained from the tumor, with a detectable agent which comprises an antibody or an antigen-binding fragment of an antibody, which selectively binds to phosphorylated S1943 residue of human myosin-IIA heavy chain and detecting any bound detectable agent,

• wherein cells of the tumor are likely to invade another organ or tissue if the sample comprises the phosphorylated S1943 residue of human myosin-IIA heavy chain, and wherein absence of a phosphorylated S1943 residue of human myosin-IIA heavy chain does not indicate that cells of the tumor are likely to invade another organ or tissue.