From Nature:
A major focus of modern medicine is treating existing conditions, but a promising approach is to try to detect elevated susceptibility to a condition before it becomes a diagnosable disease. “The pre-disease state, where someone has increased susceptibility to developing diseases, such as cancer, is widely considered the best period for intervening,” explains Yoshinori Kono, project leader at Kewpie. “Treating disease is important, but preventing disease before it strikes will reduce healthcare costs and improve quality of life.”
In the search for reliable ways to detect the pre-disease state, short snippets of non-coding RNA, known as microRNAs (miRNAs), have great potential. First discovered in 1993 in nematodes, miRNAs help to regulate gene expression.
Many human diseases, including cancer, exhibit imbalances in miRNA expression. In particular, by controlling the expression of oncogenic and tumour-suppressor proteins, miRNAs are thought to play an important role in the development of cancers by aiding tumour cell proliferation, growth-suppressor evasion and cell-death resistance. They may also promote metastasis by circulating through the bloodstream. Thus, miRNAs in the bloodstream are promising biomarkers for the pre-disease state.
More here.