If left untreated, this growth can spread beyond the lungs in a process called metastasis, into nearby tissues or other parts of the body.
Pollution, smoking (active and passive), radiation (in the form of x-rays or gamma rays)[1] and asbestos are risk factors for lung cancer.
[2] The treatment aimed at killing the cancer can also eliminate functioning lung cells (leukocytes).
There are regions on chromosomes which are highly susceptible to mutation and, if present, increase the risk of developing lung cancer.
[3][4] Abnormal gene expression in chromosome loci, such as 5p15 and 15q25, is strongly linked with the risk for developing lung cancer.
A non-synonymous variant of CHRNA5, which induces an amino acid substitution (D398N) at a highly conserved site in the second intracellular loop of the protein, is among the markers with the strongest disease associations.