This editorial describes a special issue of Statistical Applications in Genetics and Molecular Biology that presents a full report on an international competition on mass spectrometry proteomic diagnosis, recently organised at the Leiden University Medical Centre in The Netherlands.

We introduce mass spectrometry proteomic research for diagnosis from a clinical perspective, with special reference to early-stage breast cancer detection. The nature of SELDI and MALDI mass spectrometric measurement is discussed. We explain how the mass spectral data arising from this...