Molecular approach in human tumor investigation: oncogenes, tumor suppressor genes and DNA tumor polyomaviruses (review).

Molecular analysis are useful for diagnosis, prognosis and follow-up of the patients, as well as for addressing therapeutic choices. Most of the molecular methods are based on the analysis of nucleic acids. The DNA and RNA methodologies of routine applicability include Southern and Northern hybridizations and polymerase chain reaction (PCR) techniques. Southern blot hybridization recognizes major DNA rearrangements, and detection of oncogenic viral sequences present in high copy number, whereas PCR-based methods allow the detection of gross chromosomal modifications, fine gene alterations and low amount of tumor virus footprints. PCR techniques also allow the analysis of the partially degraded nucleic acids from formalin-fixed paraffin-embedded tissues. We present an overview of the use of molecular techniques for the analysis, diagnosis, prognosis and follow-up of neoplastic diseases, using examples from our experience in both leukemias and solid tumors.