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Tumor promotion is a process in carcinogenesis by which various factors permit the descendants of a single initiated cell to survive and expand in number, i.e. to resist apoptosis and to undergo clonal growth. [1] This is a step toward tumor progression. [2] [3]
Tumor progression is the third and last phase in tumor development. [1] This phase is characterised by increased growth speed and invasiveness of the tumor cells. As a result of the progression, phenotypical changes occur and the tumor becomes more aggressive and acquires greater malignant potential.
In cancer cells, major changes in gene expression increase glucose uptake to support their rapid growth. Unlike normal cells, which produce lactate only when oxygen is low, cancer cells convert much of the glucose to lactate even in the presence of adequate oxygen. This is known as the “Warburg Effect.”
The variable traits must be heritable. When a cancer cell divides, both daughter cells inherit the genetic and epigenetic abnormalities of the parent cell, and may also acquire new genetic and epigenetic abnormalities in the process of cellular reproduction. That variation must affect survival or reproduction .
They can cause cancer by turning the receptor permanently on (constitutively), even without signals from outside the cell. Ras is a small GTPase that hydrolyses GTP into GDP and phosphate. Ras is activated by growth factor signaling (i.e., EGF, TGFbeta) and acting as a binary switch (on/off) in growth signaling pathways.
Longitudinally opened freshly resected colon segment showing a cancer and four polyps. Plus a schematic diagram indicating a likely field defect (a region of tissue that precedes and predisposes to the development of cancer) in this colon segment. The diagram indicates sub-clones and sub-sub-clones that were precursors to the tumors.
Proliferation, as one of the hallmarks and most fundamental biological processes in tumors, [1] is associated with tumor progression, response to therapy, and cancer patient survival. [2] Consequently, the evaluation of a tumor proliferative index (or growth fraction) has clinical significance in characterizing many solid tumors and hematologic ...
In eukaryotes, the cell cycle consists of four main stages: G 1, during which a cell is metabolically active and continuously grows; S phase, during which DNA replication takes place; G 2, during which cell growth continues and the cell synthesizes various proteins in preparation for division; and the M phase, during which the duplicated ...