Genetic markers for head and neck cancers: Current state of art and perspectives

This article analyzes the genetic markers of planocellular head and neck cancers from the aspect of theoretical basis for their identification and application, actual state of research in this field and benefit that could be expected from their introduction into clinical practice. In spite of unquestionable progress of diagnostics and treatment of planocellular cancer of the head and neck, there has been no evident improvement of five-year survival during the last two decades, due to which the attempts have been made for global diagnostics and therapeutic orientation to be directed towards the detection of changes at molecular level. Tumor markers are defined as biochemical indicators of the existing tumors. They include the structural changes of nucleic acids (DNA and RNA), when genetic markers are in question, the development of new or modified antigens at the cell surface, the synthesis of specific plasma proteins and eutopic/ectopic hormone production. The changes of gene structure, in tumor tissue or somatic cells that are easily accessible are verified by molecular-biological techniques, and the initial step is the amplification of the genome part which is considered significant (polymerase chain reaction technique). The presence or absence of specific tumor marker, as well as its phenotypic characteristics may be verified in tumor tissue or body fluids by immunochemical methods including the immunohistochemistry before all, owing to availability of a large number of mono- and polyclonal antibodies. While some fields of oncology have been using the benefits of specific tumor markers for years, no adequate solution for the treatment of planocellular head and neck cancers can be seen yet. Currently, it is clear that there is not a single specific marker for head and neck cancer or for the group of planocellular cancers as a whole, while the literature is plentiful of different and very often contradictory findings. The greatest attention has been paid to the study of P53 gene, either isolated or in the group of other potential markers such as cycline D1, growth transformation factor, vascular endothelium growth factor, E-katherin and collagen VII. The insights obtained by these studies have encouraged the attempts to use the genetic markers for managing several crucial clinical issues, such as early detection of premalignant and malignant lesions, early detection of local recurrence and distant metastasis, early prevention of secondary tumors, and especially, the selection of patients for specific therapy.