General and tumor-type specific modifications

General and tumor-type specific modifications in nuclear organization are long-standing indications of cancer. Many cancers have alterations in the number and composition of nucleoli , the focal sites within the cell nucleus for ribosomal gene expression that supports protein synthesis. Chromosomal rearrangements are prevalent in cancer. Modifications in plasma membrane–associated receptors modify responses of the tumor cell to growth factors. Changes in integrins, molecules that mediate communication between the extracellular environment and the cytoplasm within a cancer cell, influence the transmission of information .

Cancer-related alterations occur in the exchange of signals between the cell nucleus and cytoplasm, which are critical for control of cell regulatory machinery. These changes provide insight into cellular and molecular parameters of cancer that facilitate tumor diagnosis and are targets for therapy. Effects of mutation that are found in most cancer cells are failures of molecular mechanisms that limit growth and differentiation into specialized cells, causing their death (apoptosis), their movement out of the tumor (metastasis), and the activation of a blood supply, which is required to feed the tumor (angiogenesis).