A request for the volcano plot reference was submitted and I wanted to reply with a reference to quantile volcano plots that allow the decision boundary to adapt to the data and not be defined by a hard threshold. A preprint of this method is online at http://ilya.wustl.edu/~shannon/qvp.pdf and software available from Ms. Xia Li (xli at im.wustl.edu). We are preparing this software for Bioconductor but it is ready to distribute now if anyone is interested. I hope some people find this useful. Thanks Bill Shannon Washington Univ. School of Medicine http://ilya.wustl.edu/~shannon