MITHRIL (Mirna enrIched paTHway Impact anaLysis) is an algorithm developed for the analysis of signaling pathways. It extends pathways by adding missing regulatory elements, such as microRNAs, and their interactions with genes. The method takes as input the expression values of genes and/or microRNAs and returns a list of pathways sorted according to the degree of their deregulation, together with the corresponding statistical significance (p-values).