Bone cancer is a rare type of cancer making only 0.2% of all the cancers. Bone cancer can start in any bone, but usually it starts in long bones which includes those of arms, legs and pelvis.
Bone cancer can be defined as the mutations which cause the bone cells to divide rapidly in an uncontrolled manner which, results in the formation of metastasis tumor.
Bones are an essential framework inside our body which keeps everything in shape and at a place. The adult human body is composed of 206 bones in total. The most basic structure of bone includes the outer layer of the bone which is very hard and strong. This layer is called cortical bone. Inside the cortical bone, there is a spongy structure which is termed as trabecular bone. These two layers are surrounded by a connective tissue termed as periosteum. (1)
Bones are composed of two types of cells osteoclast and osteoblast. Like all the other types of cells in the body, bone cells are continuously dividing. The cells, known as osteoclast eat up the old bones whereas, the cell osteoblast makes the new bones. Any mutation in these cells can cause cancer.
Epidemiology of bone cancer
Although primary bone cancer is rare, but it mostly affects children because their bones are growing. Osteosarcoma is the most common type of cancer people are diagnosed with. The Chinese people living in Hawaii have the highest rate of bone cancer diagnosis among the world.
1Causes of primary bone cancer
The reason behind the development of bone cancer is still unknown, but doctors believe that some factors might cause or trigger bone cancer. (2)
Some basic causes behind bone cancer include:
Genetic mutations
Certain mutations in the genes might result in cancer. A parental-transmitted genetic mutation increases a child’s risk of developing bone cancer. Some syndromes which result in genetic mutations are listed below.
- Li-Fraumeni syndrome:
Li-Fraumeni syndrome is a rare tumor predisposition syndrome. People having a genetic mutation in the TP53 gene, a tumor suppressor, have Li-Fraumeni syndrome. This mutation allows the cells to escape normal growth restrictions, which causes cancer. Li-Fraumeni syndrome increases the risk of cancer among people belonging to every age group i.e. in young as well as in adults. These patients have a 25% more chance of developing a malignant tumor by the age of 50. Soft tissue sarcomas and bone sarcomas are mostly caused by Li-Fraumeni disease.
- Retinoblastoma:
Retinoblastoma is a disease of the eye due to the mutation in the RB1 gene, which is a tumor suppressor gene. Retinoblastoma is mostly hereditary. Retinoblastoma increases the risk of the development of bone cancer and soft tissue sarcomas. The mutation in the RB1 gene results in osteosarcoma.
