Lung Cancer in Never Smokers (LCNS)

The most common cause of lung cancer worldwide is tobacco exposure (about 80% of cases), but also occurs in a peculiar group known as Never Smokers (LCNS). The LCNS presents a distinct form of lung cancer from the one that arises in ever smokers (LCES), based on etiology, molecular pathogenesis, demographics, management and clinical presentation. While it is already known what is the principal cause of LCES, is different to the LCNS cases, in which none of the possible factors can be attributed as the major cause in most of the cases.

Zhou and Zhou summarize the molecular and clinical pathogenesis of LCNS arising in East Asians. This has a special interest because the high and rising incidence that tend to occur in this population due to a combination of genetic susceptibility, geographic location and exposure to carcinogens. Moreover, in all of them, a remarkably high percent of cases arise in women. In addition, 90% of these tumors have identifiable mutations, letting them to be more likely to receive targeted therapies than tumors originated by smoking. However, LCNS arising in East Asians is well studied, but we need to increase our knowledge of many other subpopulations.

In the other hand, It has been identified some inherited syndromes with lung cancers, focusing in two rare and informative syndromes involving mutations in EGFR and HER2 genes. Surprisingly, both target relatively young women who are never o light smokers. Even though, these mutations are rare, they have a high penetrance and frequency in lung cancer development.  There are many SNPs associated with lung cancer, but combinations of various SNPs are more likely to be associated with it. In addition, there are some SNPs specifically associated with smokers, never smokers and Asian women. These findings may help identify never smokers at increased risk of developing lung cancer and maybe some of them are eligible to be in screening programs.  Along with this information, and once exists a quantitative assay for determining the presence and degree of molecular damage in an individual tumor, will give us more information about what molecules, new treatments should target. Right now, we have some information available. For example, we know that LCES tumors have a frequency of a specific mutation:

  • C>A, G>T transversions.
  • C>T, G>A transitions

And by using these two mutational changes, scientists explored several approaches to developing quantitative methods to determinate smoke related damage in lung cancer. Quantitation appears most useful for lung adenocarcinomas which include most of the lung cancers that the never smokers have.

In order to have a healthy life, doctors often give many advices to their patients so they can live a disease free life. However, with this article, showed that following that good life, not always prevents developing cancer. Cancer is a complex pathology, which is caused by environmental factors, as well as genetic factors. Reasons why is important to always be aware of any symptom that could help doctors to detect cancer in early stages.

In ALTHIAN we have several protocols for many diseases, but the majority of our studies focus on cancer treatments, such as immunotherapies. As a novel approach to treat cancer, also came with numerous secondary effects. We know is highly important to understand the protocol and be able to identify which events are related to the study drug. Please contact us and we will be more than happy to assist you.