Abstract: The invention relates to predicting or determining risk of a tumor or cancer, or the presence or absence of a tumor or cancer, in a subject. The invention also relates to methods of correlating somatic chromosomal sequence rearrangements, such as rearrangements in synteny block sequences, with the presence or probability of a tumor or cancer. The invention further relates to monitoring progression or regression of a tumor or cancer in a subject. The invention moreover relates to organizational constructs (e.g., databases) and methods of producing organizational constructs (e.g., databases) in which a plurality of somatic chromosomal sequence rearrangements predictive of the presence of a tumor or cancer are recorded or stored, for example, to correlate the somatic chromosomal sequence rearrangements with a query sample from a sample of a subject analyzed for the presence or absence of a tumor or cancer.