Cancer Genetics Cancer Is Something

Cancer Genetics

Cancer is something that has plagued mankind for all of it's history but only recently has the cause of this scourge been studied in depth. Over the last few decades scientists have studied a variety of elements which they feel are instrumental in discovering the cause, and ultimately a cure, for cancer. However, their studies have discovered that cancer is a complex disorder with numerous factors involved in its development.

Through a number of studies involving family members, twins, test animals and other means, scientists have come to the conclusion that the development of cancer can be due to a number of factors including both environmental and genetic ones. In terms of the genetic factors, it is the existence of oncogenes, or a gene "that, when mutated or expressed at high levels, helps turn a normal cell into a tumor cell," which play an important role in the development of cancer. ("What are Oncogenes") There are two types of oncogenes: cellular oncogenes, which exist in genomic DNA and may play a role in cell growth and regulation, and retroviral oncogenes which arise from errors in the replication of retroviral DNA.

The involvement of oncogenes in the development of cancer may be due to their ability to replicate, or amplify themselves, in response to environmental stress. Studies have demonstrated that cancer is directly related to the oncogenes' control of cellular signal transduction, or the cell's ability to replicate and differentiate. This includes the cell's growth factors, growth factor receptors, intracellular transduction ability, DNA binding proteins, and cell-cycle factors. In short, some oncogenes control the entire cellular function from its outer membrane to its inner nucleus.

Another factor in the development of cancer may be naturally occurring genes which suppress the formation of tumors. Called tumor suppression genes, interference with these genes may also be a contributing factor in the development of cancer. For instance, it is believed that the formation of retinoblastoma, a cancer of the eye, may be due to both the combination of an oncogene and the interference of a naturally occurring tumor suppression gene. DNA methylation is another factor in the development of cancer. DNA methylation is a process by where certain genes are silenced, or their expression suppressed. Studies have indicated that in certain types of cancers some genes are not silenced as they should be, particularly the genes responsible for cellular growth.

All these possible factors involved in the development of cancer not only work together but can do so in a multistage process; meaning that different factors can influence carcinogenesis at different times but still in conjunction with each other. The development of colorectal cancer is an example of such a process that combines both oncogenes and tumor suppression genes acting at different times but influencing each other and contributing to the development of cancer. And since these are genetic influences, they can " sometimes appear to 'run in families..'," or be carried by members of the same family. ("Genetic Testing for Hereditary Cancer Syndromes") in fact, there are a number of types of cancers that seem to cluster in familial groups; like breast, ovarian, and prostate cancers.