networkD3Sankey.js is adapted (lightly) from the networkD3 R package by J.J. Allaire, Peter Ellis, Christopher Gandrud, Kevin Kuo, B.W. Lewis, Jonathan Owen, Kenton Russell, Jennifer Rogers, Charles Sese, and CJ Yetman.
In the server code we have a cutoff where if the number of nodes surpassed 25 we dropped histology from the sankey.