There is a need to improve early detection screening methods for colorectal cancer (CRC). If detected early, CRC is highly curable. Colonoscopies are a reliable and accurate screening tool but their high cost and invasiveness lead to reduced screening rates. On the other hand, faecal occult blood tests (FOBTs) are less invasive, less expensive, have even been shown to reduce deaths caused by CRC;1 but the limited sensitivity and specificity of FOBT make it a less than ideal screening method for detecting CRC. Many researchers are trying to identify non-invasive screening methodologies, such as blood tests or faecal DNA tests,2 to improve early detection of CRC to reduce the health burden of this disease. Previous work investigated measuring circulating, tumour-associated DNA or mRNA as screens for various cancers with some success.3 In this issue of Gut, Ng et al4 (see page 1375) report their results of a study on the expression of levels of circulating microRNAs in plasma as a potential biomarker for CRC.

MicroRNAs are small, non-coding RNAs that regulate the translation of specific protein coding genes. Since their discovery in 1993, altered expression of microRNAs has been connected with several diseases, including cancer.5 Altered expression …