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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 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.
Processing of tumor antigens recognized by CD8+ T cells. Normal proteins in the body are not antigenic because of self-tolerance, a process in which self-reacting cytotoxic T lymphocytes (CTLs) and autoantibody-producing B lymphocytes are culled "centrally" in primary lymphatic tissue (BM) and "peripherally" in secondary lymphatic tissue (mostly thymus for T-cells and spleen/lymph nodes for B ...
Tumor cells have the ability to replicate the mechanisms and migration patterns typically seen in normal, non-tumor cells during various physiological processes. Like normal cells, tumor cells can activate these mechanisms to alter their shape, create favorable conditions for movement, and reshape nearby tissues to form pathways for migration.
T cells must replicate after arriving at the tumor site to effectively kill the cancer cells, survive hostile elements and migrate through the stroma to the cancer cells. This is affected by the tumor microenvironment. The draining lymph nodes are the likely location for cancer specific T cell replication, although this also occurs within the ...
Cancers are caused by a series of mutations. Each mutation alters the behavior of the cell somewhat. Cancer is fundamentally a disease of tissue growth regulation. For a normal cell to transform into a cancer cell, the genes that regulate cell growth and differentiation must be altered. [96] The affected genes are divided into two broad categories.
A normal cell initiates programmed cell death (apoptosis) in response to signals such as DNA damage, oncogene overexpression, and survival factor insufficiency, but a cancer cell learns to "evade apoptosis", leading to the accumulation of aberrant cells.
This enables the T cells to eliminate cells with "foreign" or "abnormal" antigens without harming the normal cells. It has long been debated whether cancer cells were bearing "tumor-specific" antigens, absent from normal cells, which could, in principle, cause the elimination of the tumor by the immune system.