Osteosarcoma is the most common type of solid bone cancer and second leading cause of cancer-related death among children. Many patients do not cure the current treatment of osteosarcoma is composed of a combination of chemotherapy along with surgery and, consequently, new therapies are urgently needed. In the last decade, cancer stem cells have been identified in many tumors such as leukemia, brain, breast, head and neck, colon, skin, pancreas, and prostate cancer, and these cells are proposed to play a major role in drug resistance of tumor recurrence and metastases. Recent studies have shown evidence that osteosarcoma has also cancer stem cells. This review summarizes current knowledge on osteosarcoma cancer stem cells, including the methods used for its isolation, its properties and its potential as a new target for the treatment of osteosarcoma.
Osteosarcoma Stem Cells Cancer
Osteosarcoma is the most common type of solid bone cancer, mostly occurring in children and young adults. About 6 million children each and 2 million adults will develop osteosarcoma. More commonly develop osteosarcomas in the long bones, particularly the distal femur and proximal tibia. They are often very aggressive (high grade tumors), with about 20% of patients with metastatic disease. Most commonly osteosarcoma metastases in the lungs, but can metastasize locally to other sites on the bone. Osteosarcomas are characterized by a tumor that produces osteoid. Through X-Ray, often appear as osteosarcoma tumors associated with mixed osteolytic and osteoblastic destruction of bone and soft tissue. They can be classified histologically into three types: osteoblasts, chondroblasts, and fibroblasts. microarray analysis showed significant differences in gene expression between the subtypes. 172 genes differentially expressed between osteoblasts and osteoblastic osteosarcoma.
Osteosarcoma is thought to arise from mesenchymal stem cells (MSC) or osteoprogenitor cells because of shortages in the way of differentiation of osteoblasts. Genetic instability has been the identification of the cause (s) the development of osteosarcoma difficult. Number of Ways and inactivating mutations have been invited to play a role in the development of osteosarcoma, including decreased expression of the Wnt signaling pathway and inactivation of mutations in p53 and retinoblastoma. However, none of these pathways / mutations have been implicated as causes of osteosarcoma. Paget's disease and prior irradiation are also risk factors for osteosarcoma. In a comparative study of gene expression of 22 human osteosarcoma tumors and 5 normal human osteoblasts, osteosarcoma tumors, increased expression of RECQL4, SPP1, RUNX2, and the international program and reducing DOCK5, CDKN1A, RB1, P53, and LSAMP compared with normal osteoblasts. Increase in Runx2 expression was associated with poor response to chemotherapy. High expression of cell cycle inhibitor p21/WAF1 was asked to indicate a worse prognosis (Luo et al. 2008).
Historically, all cancer cells in a tumor that is becoming more equal, resulting in a cancer cell of origin that divides again and again to produce identical daughter cells, which constitute the tumor mass. Like all cells in the tumor from a single stem cell (clones), it is estimated that each cell had the ...