Algorithms|Artifacts|Computational Biology|Computer Simulation|Data Interpretation, Statistical|Gene Expression Profiling|Humans|Microarray Analysis|Microscopy, Fluorescence|Models, Genetic|Models, Statistical|Multivariate Analysis|Nucleic Acid Hybridization|Oligonucleotide Array Sequence Analysis|Principal Component Analysis|Psoriasis|Reproducibility of Results|Sensitivity and Specificity