Abstract: Methods of detecting cancer or a particular type or subtype thereof in a subject and treating the cancer or particular type or subtype thereof. The detection can comprise determining fragmentation patterns of classifier cell-free deoxyribonucleic acid (cfDNA) from the subject and classifying the fragmentation patterns to identify the subject as being negative or positive for the cancer or the particular type or subtype thereof. The classifier cfDNA can comprise cfDNA corresponding to at least a portion of at least one exon of one or more classifier genes. The exon can comprise the first exons of the classifier genes. The treating can comprise the specific type of subtype of cancer that is detected.