In cancer treatment, non-invasive diagnosis can avoid complications of biopsy and other unfavorable impacts on patient's health. DNA, methylation, SNPs, miRNA, mRNA, protein, autoantibodies, metabolite, and Omics-based markers from remote media such as blood, plasma, and urine are emerging as noninvasive molecular markers with high specificity and sensitivity towards many cancers. In many instances, these markers are also emerging as next-generation personalized diagnostics and targets or therapeutics for personalized cancer treatment. This book classifies the available molecular tumor markers according to their principal characteristics and relative methodologies.