RESEARCH ARTICLE u i

Full list of author information is available at the end of the articleogenous factors, and is considered as systems biology diseases [1]. Despite tremendous efforts in research, the mechanism of tumor genesis and development has not been thoroughly known yet. Treatment of later stage cancers is often not therapeutically effective, and medical experts agree that early diagnosis of tumor is of great benefit to successful therapies. However, early tumor thermore, different subtypes of tumor show very different responses to therapy, indicating that they are molecularly distinct entities. Thus, accurate classification of tumor samples based on molecular signatures is essential for ef-ficient cancer treatment. Since the first paper on the clas-sification of leukemia subtype based on Gene Expression Profiles (GEP) was published [2], this research field has been studied extensively and become a research hotspot [3-8]. Many datasets on different tumors have been pub- * Correspondence