Novel molecular karyotyping techniques, such as array comparative genomic hybridization (aCGH) or gene expression analysis led to improve sarcoma classification by defining tumor-specific clusters that have potential value for resolution of differential diagnoses (e.g. wide separation of GIST from leiomyosarcoma) [53] and led to the identification of new diagnostic markers as well (e.g. DOG1 helpful in recognizing KIT-negative GIST) [54]. The gene discussed is KIT; the disease is gastrointestinal stromal tumor.