**1. Introduction**

Osteosarcoma, also known as osteogenic sarcoma, is a primary bone malignancy characterized for the production of osteoid, the mineralized portion of bone matrix [1]. Different from what its name suggests the origin of the tumor is not bone itself, but mesenchymal stem cells and osteosarcomas can also be found in soft tissues unrelated to any bone [2]. The incidence is approximately 1000 new cases each year in the United States [3]. Osteosarcoma is the third most common cancer in adolescents and is the most frequent primary bone malignant tumor in this age group. The peak incidence is between the second and third decade of life, although there is a second peak of patients aged older than 60 years of age [4, 5]. This tumor can subclassified according to histologic grade, location within the bone and the histologic characteristics of the matrix, more than 90% are of high grade, intramedullary location conventional ones [6]. The most common histologic subtypes are osteoblastic, chondroblastic, fibroblastic and telangiectatic. Additionally, these tumors can be classified as primary or secondary, depending on if the origin is in normal bone or altered bone due to prior pathology, for example Paget's disease, or radiation [7]. From a genetic perspective, osteosarcomas are characterized by highly disorganized genomic aberrations rather than a constant genetic alteration commonly found in other tumors [8]. Despite this, it has been linked to alterations in some specific genetic pathways expressed as syndromes. Such as Li-Fraumeni syndrome or Rothmund-Thomson syndrome or an alteration of the Rb protein causing retinoblastoma early in life as well as osteogenic sarcomas [9].
