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Cancer cells are cells that divide continually, forming solid tumors or flooding the blood or lymph with abnormal cells. Cell division is a normal process used by the body for growth and repair. A parent cell divides to form two daughter cells, and these daughter cells are used to build new tissue or to replace cells that have died because of ...
The hypothesis was postulated by the Nobel laureate Otto Heinrich Warburg in 1924. [3] He hypothesized that cancer, malignant growth, and tumor growth are caused by the fact that tumor cells mainly generate energy (as e.g., adenosine triphosphate / ATP) by non-oxidative breakdown of glucose (a process called glycolysis).
The cancer stem cell hypothesis proposes that the different kinds of cells in a heterogeneous tumor arise from a single cell, termed Cancer Stem Cell. Cancer stem cells may arise from transformation of adult stem cells or differentiated cells within a body. These cells persist as a subcomponent of the tumor and retain key stem cell properties.
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.”
Cancer cells, however, lose this ability; even though cells may become grossly abnormal, they do not undergo apoptosis. The cancer cells may do this by altering the mechanisms that detect the damage or abnormalities. This means that proper signaling cannot occur, thus apoptosis cannot activate.
The evolutionary processes do not cease when a population of cancer stem cells arises in a tumor. Cancer treatment drugs pose a strong selective force on all types of cells in tumors, including cancer stem cells, which would be forced to evolve resistance to the treatment. Cancer stem cells do not always have to have the highest resistance ...
Illustration of how a normal cell is converted to a cancer cell, when an oncogene becomes activated. An oncogene is a gene that has the potential to cause cancer. [1] In tumor cells, these genes are often mutated, or expressed at high levels. [2]
There are several mechanisms that lead to escape of cancer cells to immune system, for example downregulation or loss of expression of classical MHC class I (HLA-A, HLA-B- HLA-C) [7] [4] which is essential for effective T cell-mediated immune response (appears in up to 90% of tumours [7]), development of cancer microenvironment which has ...