Molecular mechanisms in cancer: what should clinicians know?

Normal cells are influenced by a variety of environmental and host influences that can produce pro-carcinogenic mutations. Either a single or a series of mutations might result in cellular transformation. Like normal cells, most cancer cells use multiple redundant intracellular signaling pathways to ensure the maintenance and viability of functions critical to their survival. Thus, cellular pathways that are integral to cell function, survival, proliferation, and receptor expression are potential targets for therapeutic intervention. One example of this is the epidermal growth factor receptor signaling pathway. Other potential targets are molecules that mediate processes through which tumors produce angiogenic and invasion factors that stimulate host blood vessel growth into tumors and allow tumor growth and metastasis, such as the vascular endothelial growth factor. Targeting of downstream events that result in cellular apoptosis is another potential strategy. Continued investigations may result in the development of proteomic profiling databases through which a patient might be matched with molecular signatures in a library and upon which individualized cancer therapies might be selected. In this way, clinicians might recommend combinations of molecularly targeted agents and other therapies on the basis of an individual patient's proteomic profile.