Abstract: This invention relates to a process for recognizing signatures in complex gene expression profiles that comprises the steps of: a) making available a biological sample that is to be examined, b) making available at least one suitable expression profile, whereby at least one expression profile comprises one or more markers that are typical exclusively of the expression profile, c) determining the complex expression profile of the biological sample, d) determining the quantitative cellular composition of the biological sample by means of the expression profiles determined in steps b) and c). In addition, the process according to the invention can comprise the steps of e) calculating a virtual signal that is expected based on the specific composition of the expression profile, f) calculation of the difference from the actually measured complex expression profile and the virtual signal, and g) determination of the quantitative composition of the complex expression profile based on the determined differences.