Scientists have uncovered new evidence supporting the hypothesis that the genetic background plays a role in determining how likely it is that a smoker will develop lung cancer and what type of cancer it will be. Genome-wide association studies by Cancer Research UK-funded scientists at the Institute of Cancer Research implicated DNA variants within regions on chromosomes 5, 6, and 15.
The work is published in Cancer Research in a paper titled “Deciphering the impact of common genetic variation on lung cancer risk.”
The latest ICR work suggests there are two independent sites on chromosome 15 involved in determining lung cancer risk. They calculated that current or former smokers carrying one copy of each of the chromosome 15 variant were at a 28% higher risk of developing lung cancer than smokers without the variants. The relative risk jumped to 80% for either former or current smokers who were homozygous for both chromosome 15 variants. The increased risk of lung cancer was not evident in carriers of the polymorphisms who had never smoked.
Additionally, the sequences on chromosomes 5 and 6 were found to influence the type of lung cancer smokers developed. Individuals who carried the chromosome 5 variation were more likely to develop adenocarcinoma, a type of non-small-cell lung cancer (NSCLC) that represents the most common form of the disease, the ICR researchers point out. The chromosome 6 variant also appeared to influence whether the carrier developed the adenocarcinoma or the squamous cell carcinoma form of NSCLC.