A research team in Taiwan has identified cancer-initiating cells in KRASG12D mutant gene-induced lung adenocarcinoma, one of the most common types of lung cancer, which may contribute to the search for lung cancer treatments, Academia Sinica, the nation’s top research institute, said yesterday.
The institute said lung cancer is the leading cause of cancer-related mortality worldwide and is also one of the most commonly diagnosed malignancies in developed countries, as well as a growing problem in developing countries.
About 41,000 people died of cancer in Taiwan last year, 20 percent of which were of lung cancer, the institute said, adding that lung cancer has been the leading cause of cancer-related deaths for Taiwanese women over the past 20 years.
The research from a team led by John Yu (游正博), a distinguished research fellow at Academia Sinica’s Institute of Cellular and Organismic Biology, was published in the journal Cancer Research last month.
The team said there are two common types of lung cancer — small-cell lung cancer (15 percent of cases) and non-small-cell lung cancer (85 percent) — and the medical field has found that the mutation on the KRAS oncogene’s codon 12 (the 12th codon set on the gene) was found in 30 percent of the non-small-cell lung cancer cases.
The team established a new model of lung cancer in mice that enabled them to control the KRASG12D gene with a “molecular switch,” which can turn the cancer gene on and off and thereby control the formation and progression of lung cancer.
Team member Cho Huan-chieh (卓煥傑), a doctoral student from the Graduate Institute of Microbiology and Immunology at National Yang-Ming University, used the model to identify the specific cell types from which non-small-cell lung cancer originates.
The team discovered that most malignant tumors arose from bronchiolar Clara cells and that they have attributes consistent with cancer-initiating cells, in that the tumor not only renews itself, but can also differentiate into heterogeneous tissue types.
Yu said tumors of bronchiolar origin are more malignant because the tumor cells can upregulate genes that activate cell growth and downregulate genes that inhibit cell growth, therefore bronchiolar cells are likely to be the origin of malignant lung cancers.
Academia Sinica said the findings could contribute to the development of new methods to detect lung cancer in humans earlier and treat them more effectively.