There is growing enthusiasm for early detection of cancers. Technological inventions allow us to identify molecular events that will effectively detect cancer earlier in biological specimens. This approach enables us to develop molecular biomarkers for detecting cancer early. It is believed that such a molecular marker approach may not only enable the detection of the disease earlier, but may also improve earlier therapeutic interventions and better survival and quality of life. Biomarkers are poised to play a critical role in meeting the expectations of cancer patients by making available the assays and tests that can detect these biomarkers in biological specimens that can be obtained by non-invasive means. For molecular detection, it is necessary to understand the biological nature of carcinogenic transformation and genetic and molecular changes leading to preneoplastic lesions. Unfortunately, not many biomarkers are available today that can be successfully applied into clinical settings. For the successful translation of the biological innovations, it is necessary for them to be systematically evaluated before they can be applied in the clinic. Successful development of biomarkers depends not only on the approaches to understanding the biology of carcinogenesis, but also on the application of state-of-the science technological approaches for detecting changes that occur at cellular, genetic, molecular and protein levels. With the completion of sequencing of the human genome, various molecular approaches, have accelerated in the discovery and development of molecular markers for the detection of cancer.