Disclosed herein are methods for determining whether a subject is suffering from Waldenström
macroglobulinemia (WM) or a precursor condition thereof, or
multiple myeloma (MM) or a precursor condition thereof. These methods comprise determining, in a sample obtained from the subject, data indicative of the proportions of two or more immune
cell populations. Methods of monitoring a subject with WM, or a precursor condition thereof, are also disclosed. These methods comprise determining in
tumor cells obtained from a sample obtained from the subject and a
reference sample expression of two or more
gene expression signatures which indicate whether the subject is at risk of
disease progression.