As cells change from normal to abnormal cells (dysplasia), a stage that could suggest the beginnings of cancer, the microRNAs (miRNAs), which are short stretches of genetic material, can change. A study of cells taken from bronchial biopsies has shown a fall in the levels of a microRNA known as miR-34c as cells become abnormal, which could be used as a lung cancer biomarker in diagnosis, or as an endpoint in trials.
In a lung cancer prevention trial study presented at the AACR-IASLC Joint Conference on the Molecular Origins of Lung Cancer, researchers looked at a range of 14 miRNAs in cells from initial and follow-up bronchial biopsies in 125 people taking part in the study. They found that expression of miR-34c was lower in cells that had become abnormal.
"To understand how lung cancer occurs, it is important to know what happens in normal tissue and in tissue that has become a cancerous or precancerous lesion," Dr. Celine Mascaux, Ph.D., of the University of Colorado in Aurora, told MedPage Today. "Our results show that miR-34c is downregulated when histology is upgraded from normal bronchial tissue to high-grade bronchial lesions, independently of treatment and smoking status. Because of that, we think that miR-34c expression is a good reflection of baseline histology and histology changes."
Because of their very nature, chemoprevention trials could potentially run for many years, and so need biomarkers as surrogate endpoints. Finding a biomarker for lung cancer could support these types of trials, allowing researchers to run shorter trials and helping companies to get drugs that could prevent cancer onto the market more quickly. As well as providing a clue to a useful biomarker, these results have also helped researchers understand a bit more about how lung cancer develops.
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