Preliminary Study Of Tumor Stem Cells In Nasopharyngeal Carcinoma

In the paper of "Prospective identification of tumorigenic breast caner cells" published on PNAS by 2002, the author, Al-Hajj, demonstrated that there are different subpopulation in the breast cancers and only a small set of subpopulation (ESA~+CD44~+CD24~-) can generate tumors in nude mice. These tumors, similar to that of the original patient specimens, consist of heterogeneous cells. It is the first time that the existence of tumor stem cells was confirmed. Thereafter, Hemmati HD and Singh SK identified the brain tumor stem cells in 2003. The facts that tumor stem cells can be identified in somatic tumors made a great change on cancer therapy in our mind. The confirming tumor stem cell has important influence on the tumor research and therapy. If tumors are derived from tumor stem cells and tumor metastases come from a set of tumor stem cells, therapy of tumors must aim at tumor stem cells and eliminates them. If the tumor stem cells have not been cleared, then relapse and metastasis may be inevitable. Therefore, isolation and identification of tumor stem cells has become a new hot spot in tumor research.Nasopharyngeal carcinoma (NPC) is an endemic cancer with high incidence in Southeast Asia and Southern China, which obviously shows an ethnic aggregation and geographic distribution. Nasopharyngeal carcinogenesis is a multistage process involving interactions with multiple factors. Epstein-Barr virus (EBV), some chemical carcinogens and genetic factors are all thought to be closely associated with NPC. A clinical characteristic of NPC is early metastasis to cervical lymph nodes and high incidence of remote metastasis. Although great progress in the radiotherapy and imaging diagnosis of NPC have been made in the late 90s, the cure rate of NPC has not been improved yet and 5 year survival rate still remained around 50-60%. Despite of improvements on treatment modalities, local recurrences and remote metastasis occur frequently in NPC patients, which are a leading cause of death. Till now, there are no articles reported that there exist tumor stem cells in NPC. Identification of...