Dea all, I am planing to analyze 4 sample that have been prepared with the small sample target protocol for the human plus2.0 chip I remember of a paper by Irizzary on a modified RMA for small samples. Can someone give a suggestion on the analyse to run, better the classical RMA, the small sample RMA o something else? Thank you Marco -- --------------------------------------- Marco Fabbri Istituto Clinico Humanitas via Manzoni, 56 20089 Rozzano (Mi) Tel. 028224 5130 Fax 028224 5101