Researchers have identified a specific group of microRNA molecules that are responsible for controlling genes that cause breast cancer metastasis. The study, led by scientists at Memorial Sloan-Kettering Cancer Center (MSKCC), appears in the January 10, 2008, issue of Nature. MicroRNAs are known to inhibit the activity of entire sets of genes associated with cancer metastasis – a process that leads to the majority of cancer-related deaths. The new work explains how the loss of certain microRNAs allows cancer cells to migrate through organ tissue and to grow more rapidly. The researchers examined human breast cancer cells with strong metastatic ability and found that the cells had lost large numbers of three different microRNA molecules. Conversely, when researchers put those molecules back into human breast cancer tumors in mice, the tumors lost their ability to spread.
