Focus on the Lung Part One: Risk and Oncogene Mutations

Lung cancer is the leading cause of cancer in the US among both men and women.
In the 1960's the Surgeon General's Report loosely associated cigarette smoking with cancers of the trachea, lung, bronchus, larynx and lip.

Within the past two decades, cigarette manufactures have changed the design of their product adding filters that remove much of the tar from inhaled tobacco smoke. These filters also retain more of the nicotine causing deeper inhalation by smokers and a longer smoke retention period within the lung to satisfy nicotine cravings. This has resulted in a shift in histology patterns with decreasing amounts of squamous cell carcinoma and increasing amounts of adenocarcinomas being reported.

Cigarette smoke emits about 4,800 compounds. Lung cancer develops from chronic exposure of cell DNA to metabolically active carcinogens. These compounds can alter and damage DNA in a number of ways including chromosonal aberrations, DNA stand breaks, and oncogene inactivation. Geneic factors also play a role in the risk of developing lung cancer.

Risk Factors: Age related increase in lung cancer is lowest in men and women who have never smoked, an intermediate risk in those that have quit at various ages, and highest in those who continue to smoke. Factors to look for include: duration of smoking, number of cigarettes per day, and age at time time of smoking cessation

• The longer one lives after cessation of smoking the greater the risk of developing lung cancer.
• The greater the consumption of tobacco, the greater the risk of developing lung cancer.

Occupational expose can also contribute to the development of lung cancer. Examples include graphite electrode manufacturing, coke oven plants, exposure to diesel exhaust, workers exposed to cadmium, and those working in the synthetic rubber and various plastics.

Predictive markers of survival metatasis, gender and weight loss. Some studies indicate that weight loss in lung cancer patients is associated with poor therapy outcome and reduction in patient survival, though how weight loss affects survival outcome is not clear.

Oncogene mutation: K-ras mutations are found in adenocarcinoma, not in small cell carcinoma, and are not associated with a patients sex, prior therapy status, or tumor extent. p53 tumor suppressor gene is inactived by mutation in more than 50% of non-small cell lung carcinomas and is found in 90% of small cell lung carcinomas. In early stage lung cancer, sputum can sometimes reveal K-ras or p53 cellular mutations. EGFR has been associated with lung tumor progression.

Information taken from the text: Oncology An Evidence Based Approach
http://www.amazon.com/Oncology-Evidence-Based-Approach-Chang/dp/0387242910