A new study in Europe and the United States has found that lung cancer can have a latent period of more than 20 years in the body before suddenly developing into an untreatable malignancy. The results underscore the need to develop methods that can diagnose lung cancer early. The study, published in the journal Science, analyzed seven lung cancer patients, including smokers, ex-smokers and never-smokers, and found that lung tumor cells triggered by an initial genetic error are like seeds that can lurk in the body for years, “growing” undetectably and then being “triggered” by a new genetic error when conditions are right. Then, when the conditions are ripe, they are “triggered” by a new genetic error and “emerge” publicly and rapidly grow into malignant tumors. During the rapid growth phase of a tumor, multiple forms of genetic errors appear in various regions of the tumor, causing each region to develop in a different path, giving each part of the tumor its own genetic identity. The reason many targeted therapies have had only limited success is that they only attack specific genetic errors. Charles K. Swanton, a Cancer Research UK professor involved in the study, said in a statement. Swanton said in a statement, “Lung cancer survival rates are abysmally low and many of the new targeted therapies have limited effectiveness. By understanding how lung cancer develops, we have opened the book on its evolutionary rules and hopefully we can begin to predict its next steps.” The study also shows that many of the early genetic errors associated with lung cancer are caused by smoking. As the disease progresses, however, smoking or not is less important, and later genetic errors are more often associated with a protein called APOBEC. About 1.8 million new cases of lung cancer are diagnosed worldwide each year, two-thirds of which are already advanced when detected, and only about 10 percent of patients survive beyond five years after lung cancer is diagnosed. The latest research suggests that if lung cancer is detected early and nipped in the bud before it begins to develop along multiple evolutionary pathways, the situation could be very different and more lung cancer patients would survive.