The present invention provides a binding moiety which selectively binds to Sox11 protein and/or mRNA for imaging, diagnosis or prognosis of lymphomas, such as mantle cell lymphomas (MCL) and diffuse large B-cell lymphoma (DLBCL). Optionally, the moiety is an antibody or antigen-binding fragment thereof. Advantageously, moiety comprises a further, readily detectable moiety. The invention also provides methods of imaging lymphomas cells as well as methods of diagnosing or prognosing lymphomas in an individual. A further aspect of the present invention provides a method of identifying cells associated with lymphomas, the method comprising analyzing the pattern of gene expression in a sample of cells to be tested and comparing it to the pattern of gene expression in a sample of known lymphomas cells. Preferably, the cells to be tested are identified as lymphoma cells if the expression of Sox11 is upregulated compared to normal B-cells.
