For example I was doing research for trying to find the cause of why low levels of vitamin D were causing cancer initiation. It turned out that vitamin D was down regulating cell division by up regulating the destruction mechanism of the ubiquitin system for a specific transcriptional molecule.
When I was asked to research why high blood levels vitamin d were reducing risk of metastasis I used design as a working hypothesis. I used a common mechanism as a working assumption and this turned out to be a tremendous short cut.