Microarrays can provide a broad picture of the state of a cell by monitoring the expression level of thousands of genes at the same time. As such the technique can give valueable information on many biological processes. In particular in relation to tumors a precise classification is of importance for finding the optimal treatment.
Microarray data poses many interesting statistical problems. The raw data consists of an image of scanned pixel values and the location of a particular gene must be identified. Often there will be outliers in the data that need to be detected. A fundamental but very difficult question is the precise translation of a pixel value to the number of molecules present. Due to the variation in the production of the chips and the variation in the preparation of the samples the data from two arrays cannot be compared before a normalization has been made. This seems to be a nontrivial task and unless done very carefully one may introduce systematic errors. There seems to be a need of establishing an accepted standard for the normalization process. Coming to the estimation of the actual expression level of a gene one is still lacking a systematic study delineating the part of the variance due to the measurement technique and the part due to biological variation. Also for the Affymetrix system it is a very interesting question how to use best the information in the mismatch probes. When comparing two groups and searching for genes that are differentially expressed in the two groups one faces the problem of multiple comparisons. Obviously, if only a small number of genes participate in the difference between the two groups and we have no prior information as to what group of genes the differentially expressed genes belong to we are facing a problem when the chip contains a huge number of genes. Many microarray studies are used for classification and clustering. The maximum likelihood classifier based on independent normally distributed values seems to be one of the better choices. The assumptions for using this classifier needs to be checked and perhaps the modelling of the distributions can be improved. Underlying the above points are also the problem of designing the experiments so as best to extract the information.
It is the intention of the workshop to cover most of the aspects mentioned above.
Wednesday February 19  

19:0021:00:  Registration and gettogether  
Thursday, February 20  
08:3009:30:  Registration  
09:3009:40:  Welcome  
09:4010:25:  Claus Mayer (Rowett Research Institute, Aberdeen, Scotland): Least trimmed squares methods for microarray normalization  
10:4011:10:  Coffee/tea  
11:1011:55:  David Edwards (NOVO Nordisk, Denmark): On the preanalysis of onechannel cDNA microarray data  
12:1013.30:  Lunch  
13:3014:15:  Torben F. Ĝrntoft (Molecular Diagnostic Laboratory, Aarhus, Denmark): Microarrays, basic principle and use in medical research  
14:3015:15:  Yudi Pawitan (Department of Medical Epidemiology, Karolinska Institute, Stockholm): Survival analysis using gene expression data  
15:3016:00:  Coffee/tea  
16:0016:45:  Mark van der Laan (University of California, Berkeley): Statistical inference with gene expression data  
Friday, February 21  
09:1009:40:  Mette Langaas (Department of Mathematical Sciences, Norwegian University of Science and Technology, Trondheim, Norway): Estimating the number of genes truly differentially expressed  
09:5010:20:  Jörg Assmus (Department of Mathematics, University of Bergen, Norway): On the problem of significant pvalues for gene expressions  
10:3011:00:  Coffee/tea  
11:0011:45:  Jelle Goeman (Leiden University Medical Center, The Netherlands): A global score test for differential expression of groups of genes in highdimensional microarray data  
12:0014.00:  Lunch  
14:1014:55:  Mats Rudemo (Mathematical Statistics, Chalmers University of Technology, Göteborg, Sweden): Empirical Bayes analysis of variance models for microarray data  
15:1015:40:  Coffee/tea  
15:4016:25:  Ernst Wit (Department of Statistics, University of Glasgow, U.K.): Hidden Markov modelling of genomic expression interactions  
16:4017:25:  Arnoldo Frigessi (Norwegian Computing Center, Oslo, Norway): Towards a comprehensive statistical model of cDNA microarrays  
18:30:  Workshop dinner  
Saturday, February 22  
09:0009:45:  Rafael Irizarry (Department of Biostatistics, Baltimore, USA): Getting usable data from microarrays: The role of statisticians  
10:0010:30:  Coffee/tea  
10:3011:15:  Steen Knudsen (Technical University of Denmark): A new nonlinear normalization method for reducing variablility in DNA microarray experiments  
11:3012:15:  Volkmar Liebscher (Institute of Biomathematics and Biometry, München, Germany): Stochasting modelling and quality control for gene expression data  
12:3013.15:  Lunch  
13:1514.00:  Anja von Heydebreck (MaxPlanckInstitute for Molecular Genetics, Division of Computational Molecular Biology, Berlin, Germany): Error modelling, data transformation and robust calibration for microarray data  
14:1514:45:  Coffee/tea

The registration fee, covering lunches, is DKK 400, payable in cash in Danish currency upon arrival at the workshop.
Do not hesitate to contact the MaPhySto secretariat
(at maphysto@maphysto.dk
)
for more information.
(This announcement in [ postscriptformat  pdfformat ])