^{Immunology and Oncology}

The molecular classification of Tumor is actually arrangement analysis disguised as classification. In a typical gene expression array study, the researcher will look at a cluster of tumors of a specific type. Cluster analysis of the gene expression array values will help discrete the tumors into groups with common expression patterns. Some of these groupings will prove to have a detailed biologic feature (e.g. increased tendency to metastasize, higher response to a chemotherapeutic agent, lengthened existence). Cancers are not just masses of malignant cells but complex ‘rogue’ organs, to which many other cells are recruited and can be degraded by the transformed cells. Interactions between malignant and non-transformed cells create the Tumor microenvironment (TME). Experts stress that these techniques have been tested in only small trials, and they don't always work. But the results have raised hope that immunotherapy may give doctors new options for treatment in the future.