Identification of novel diagnostic markers by differential display

Accurate and early diagnosis of a disease state such as a viral infection, or in a more complicated situation cancer, means live saving because proper medical interventions can be applied in a timely manner before it is too late to treat the disease. Thus it is crucial that good diagnostic markers for any relevant diseases can be obtained. The markers can be in the form of DNA such as viral integration or chromosomal DNA aberrations including deletions, translocations, and point mutations. As a result, these genetic abnormalities, in turn, may lead to altered gene expressions, such as new genes being turned on. Therefore, the markers can also be in the form of mRNAs or their protein products. DNA-based diagnosis is now done mostly with amplification technology breakthroughs such as polymerase chain reaction (PCR). However, protein based diagnosis such as a blood antibody test for a disease specific antigen (e.g., HIV and HPV virus infections; prostate-specific antigen for prostate cancer) are more accurate, convenient, and noninvasive. Traditionally, a good diagnostic marker for an infectious disease can be obtained by identifying the etiological agent such as a venues or a bacterium, which may not be always easy. But for noninfectious diseases such as cancer, a good marker may be even harder to come by because the alteration is more subtle and difficult to detect.