Holger Sültmann1, Sven Diederichs2. 1. Cancer Genome Research Group, German Cancer Research Center and National Center for Tumor Diseases, Heidelberg, Germany. 2. Helmholtz-University-Group "Molecular RNA Biology and Cancer", German Cancer Research Center and Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany. Electronic address: s.diederichs@dkfz.de.