[Cytogenetics of oral solid tumors]

The tumorigenesiss of oral solid tumors is still uncertain. The underlying mechanisms of epithelial or connective tissue proliferation are not yet fully understood. Also, the transformation of a benign tumor into malignant is obscure. Cytogenetics is the study of chromosome number and structure using a light microscope. Human chromosome nomenclature is based on An International System for Human Cytogenetic Nomenclature (ISCN). The normal human somatic cells have 46 chromosomes, including 22 pairs of autosomes and two sex chromosomes, XX in female and XY in male. The chromosome abnormalities can be numerical and structural. Both types can occur concurrently. Numerical abnormalities involve the loss and/or gain of a whole chromosome and can include both autosomes and sex chromosomes. Cells which have lost a chromosome are categorized as a monosomy, while those with an extra chromosome are trisomy. Structural abnormalities include translocations, deletions, inversions and insertions. Cancer, in its various forms is a result of genetic changes. This concept comes from the finding of chromosomal abnormalities. These abnormalities may arise as a consequence of random replication errors; exposure to carcinogens; or damaged DNA repair process. In clinical oncology, the study of chromosome abnormalities in solid tumors provides valuable information for the diagnosis, evaluating treatment response of metastatic cancer, marker for prognosis and targeted therapy. In tumors which histologic features overlap, cytogenetics plays an important role for diagnosis. Cytogenetics has also been used to monitor the surgical margins of the resection in head and neck carcinoma, where the histology was not definitive. The present report will focus on the role of cytogenetics in the diagnosis and prognosis of benign and malignant oral solid tumors.