Lung Cancer, More Than Meets the Eye

Adenocarcinoma genetics breakdown into bronchoid squamoid magnoid

(RxWiki News) While there are three main kinds of lung cancer, it seems that the genetics of each are more complicated than anyone had guessed.

The same team that originally laid out the differences between bronchoid, squamoid, and magnoid cancers back in 2006, recently published their findings that each category has elaborate genetic differences.

"Ask your oncologist about genetic evaluation of your cancer."

Researchers from the University of North Carolina School of Medicine found that among other evaluations of the DNA, the profile of mutations in several genes indicated what category the lung cancer fell into, and the most important genes were EGFR, KRAS, STK11, and TP53.

In a genetic study of the types of lung cancer called adenocarcinoma, advanced statistical techniques evaluated the DNA of 530 lung cancers for patterns.

While each cancer is traditionally classified based on appearance under a microscope, scientists were interested to see if the genetics told the same story.

Several of these are well known cancer genes, and pharmaceuticals targeting these genes specifically are under development, in various stages of testing.

By far the most relevant data from the study was the effect of different mutation profiles on response to standard chemotherapies, as well as the overall survival of the patients over a five-year period.

Published results found similar data to previous studies, and the three classifications of solid lung cancer (adenocarcinoma) had different patient groups. Bronchoid was most common in females who did not smoke, and was likely to be early stage and low grade with little metastasis.

Squamoid cancers were the highest grade, and the largest. Magnoid tumors were most likely to be found in smokers, especially the heaviest smokers.

Neil Hayes, MD, MPH, associate professor of medicine, says, "It has been known for about a decade of using gene expression arrays that "molecular subtypes" exist. These subtypes have molecular "fingerprints" and frequently have different clinical outcomes. However, the underlying etiologies of the subtypes have not been recognized. Why do tumors form subtypes?"

"Our study shows that tumor subtypes have different underlying alterations of DNA as part of the difference. These differences are further evidence of the importance of subtypes and the way we will use them. For example, the mutations are different which may imply much more ability to target than previously recognized."

The study was published on May 10, 2012 in the journal PLoS One.

Funding was provided by the National Cancer Institute, National Heart, Lung, Blood Institute, the Thomas G. Labrecque Foundation, the Lineberger Comprehensive Cancer Center Translational Small Grants Program, and the authors disclosed ownership and involvement in a related company GeneCentric Diagnostics, as well as a related patent.

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Review Date: 
May 15, 2012