Lung cancer tumors different in smokers compared to non-smokers

A new study says that lung cancer tumors in those who smoke and those who never smoked have different DNA alterations in the tumor genomes.

The lung cancer tumors of those who had never smoked had twice as many DNA abnormalities as people who were current or former smokers, said study author Kelsie Thu, who is based at the BC Cancer Research Center in Canada. She believes that oncologists are in fact dealing with two forms of cancer.

The team of researchers found regions of DNA that showed mutations in both groups, such as those that code for epidermal growth factor receptor (EGFR), which is typical, but the never-smoker tumors genomes contained twice as many DNA alterations overall.

The findings of this study show similar results to previous research, including a 2007 review in the journal Nature and a 2007 review in the Journal of Thoracic Oncology that suggested cancer in smokers and never-smokers arises from different mechanisms. However, the new study looked beyond mutations of a single gene, and found whole regions of DNA alterations to be different in the lung tumors of smokers compared with never-smokers.

Lung cancer was the second-leading cause of death in the U.S. after heart disease.

There are two main types of primary lung cancer, small cell lung cancer and non-small cell lung cancer. About 1 in 5 lung cancers are small cell; the rest are non-small cell.

Up to one-fourth of all people with lung cancer may have no symptoms when the cancer is diagnosed. These cancers usually are identified incidentally when a chest X-ray is performed for another reason.

Signs and symptoms of lung cancer can include:

* A persistent cough and gets worse over time
* Persistent chest pain
* Coughing up blood
* Shortness of breathe
* Wheezing
* Change in voice
* Getting sick with pneumonia and bronchitis a lot
* Swollen neck and face
* Loss of appetite, weight loss
* Feeling fatigued or lethargic