domingo, 4 de noviembre de 2018

Lung Cancer Genetics

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Lung cancer is a disease involving uncontrolled multiplication and growth of the cells in the lung tissue that caused by changes in certain genes in the body.

In some cases, these gene mutations may be inherited from a family member with the disease, although most patients with lung cancer develop a genetic mutation due to environmental exposure to carcinogens.

The two most common gene mutations that are linked to lung cancer, EGFR and KRAS, are discussed in more detail below, in addition to several other genes that may also play a role.

Somatic and Inherited Gene Mutations

Somatic mutations refer to genetic changes that are acquired throughout a person’s lifetime, which are not inherited at birth. This includes changes caused by environmental factors, such as damage caused by exposure to cigarette smoke.

If a gene mutation is inherited from a parent that is affect by the disease, it is thought to follow an autosomal dominant inheritance pattern. This means that only one parent needs to carry a genetic mutation as one copy of the gene is sufficient to increase the risk of the disease.

It is worth noting, however, that not all individuals that inherit a gene mutation for lung cancer will suffer from the disease. This is thought to be due to related environmental factors that affect the pathogenesis of the disease.

Epidermal Growth Factor Receptor (EGFR)

EFGR is a key gene in the pathology of lung cancer and is present in up to half of all cases. It is involved in the production of a receptor protein, which become embedded into the cell membrane and regulate signaling pathways of cell growth and proliferation.

A mutation in the EGFR gene can alter the proteins that are produces leading to constant activation of the signaling pathways and, as a result, uncontrolled growth of the cells.

EGFR is a suitable target in the treatment of the disease and there are several drugs that manipulate its action in the production of proteins and resulting effects, including gefitinib, erlotinib and cetuximab.

Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS)

Similarly to the EFGR gene mutation, KRAS is a GTPase that is involved in a high proportion of cases of lung cancer. Its role is to produce the K-Ras protein, which regulates the division of cells via the RAS/MAPK pathway.

When there is a mutation in the KRAS gene, the division of cells can occur in an uncontrolled manner and lead to the formation of a tumor and the pathogenesis of lung cancer.

Other Gene Mutations

There are also several other genes that have been associated with the pathogenesis of lung cancer. Specifically, mutation in the following genes may be involved in causing the disease:

MET
LKB1
BRAF
PIK3CA
ALK
RET
ROS1

Each of these gene plays a role in the regulation of cell growth and proliferation in the lung tissue. It is for this reason that a mutation in one of these genes can lead to abnormal growth of the cells and the possible presentation of cancerous tissue, the beginning of lung cancer.