The presence of only five tiny strands of RNA is enough to clearly distinguish cancerous thyroid tissue from otherwise normal tissue, scientists say. The findings provide more evidence that an emerging set of RNA genes called microRNA (miRNA) is a powerful regulatory force in the development of cancer and other diseases. The study is published online in the Dec. 19 Proceedings of the National Academy of Sciences. Scientists already know that some people inherit a predisposition to developing papillary thyroid cancer (PTC), the most common form of thyroid cancer, representing about 80 percent of all cases. Although changes in key cell-signaling systems and gene translocations are sometimes present in thyroid tumors, no specific gene mutations have yet been identified that are directly linked to the predisposition of this type of cancer. That led researchers in The Ohio State University Comprehensive Cancer Center to conclude that while genetic mutations may indeed cause some people to be more likely to develop PTC than others, the mutations may not occur often enough to be readily detectable. They hypothesized that any predisposition to PTC might be more reasonably linked to a more subtle, complex interaction among several genes – suggesting a possible role for miRNAs.
