The schema attests for the robustness of the original concept that all the different molecular classification methods tend to assign individual patients, with reasonably high concordance, to the same molecular subtype.
The clustering of tumours into different groups that share patterns of gene expression has led to subdivisions and molecular classifications of lung adenocarcinomas in particular [116 120].
Molecular classification of different cancers, such as colorectal and lymphoma, has consistently stratified tumours into sub-types with prognostic outcomes independent of those suggested by conventional clinical staging procedures [8], [9].
This suggestion is supported by previous studies describing an impact of miR-126 in molecular classification of different RCC subtypes [ 12, 16, 17].
In RCC miR-126 is described to play a role in molecular classification of different subtypes [ 12] and recently, association of downregulation with progression was supposed [ 16, 17].
Analyses of the global expression profile of patients have lead to the molecular classification of MM patients in different disease subtypes (Zhan et al, 2006).
Based on gene expression, a molecular classification of glioblastoma into four different profiles called ProNeural, Neural, Classical and Mesenchymal was recently proposed [ 23].
Different classifications are said to lead to the same molecular classification of breast cancer in the five subtypes, however, a recent study by Weigelt et al. [ 16] contradicts this assumption.
Recent gene expression profiling studies on breast cancer showed that molecular classification of tumours based on the gene expression patterns can identify clinically different subtypes of cancer with different prognosis or disease outcome [ 3, 4].
The molecular classification of breast cancer has an important prognostic value: the single subtypes have different prognosis and show different responsiveness to specific therapies.
