口腔癌の浸潤・転移における分子メカニズム

Abstract

Cancer is now the leading cause of death in Japan. A rapid increase in cancer mortality is expected as Japan is facing as uper-aged society. Oral cancers rank sixth among the common malignancies globally, with a rising titer of around 40% in developing countries such as Southeast Asia. More than 90% of malignant neoplasms of the oral cavity and oropharynx are squamous cell carcinomas of the lining mucosa. Review of the literature indicates that the most important factor for the high mortality rate is the advanced stage of the disease at the time of diagnosis and treatment. In the prognosis of oral cancer, the extent of lymph node metastasis is a major determinant. Like most epithelial cancers, oral cancer develops through the accumulation of multiple genetic and epigenetic alterations in a multistep process. Recent molecular studies have advanced our understanding of the disease and provided a rationale to develop novel strategies for early detection, classification, prevention, and treatment. Attempts to identify the genes involved in the metastasis are pivotal for the early prediction of oral cancer behavior. However, the identity and time of onset of the alterations that endow cancer cells with these metastatic functions are largely unknown. The process of metastasis consists of sequential and selective steps including proliferation, induction of angiogenesis, detachment, motility, invasion into circulation, aggregation and survival in the circulation, cell arrest in distant capillary beds, and extravasation into organ parenchyma. In this review, we introduce recent findings of the molecular mechanism of oral cancer invasion and metastasis.