Characteristics of Cancer Cells
1. They are usually less well differentiated than normal cells or benign tumor cells. The presence of invading cells is the most diagnostic indication of a malignancy.
2. Cancer cells can multiply in the absence of growth-promoting factors required for
proliferation of normal cells and are resistant to signals that normally program cell death (apoptosis).
3. Cancer cells also invade surrounding tissues, often breaking through the basal laminas that define the boundaries of tissues and spreading through the body to establish secondary areas of grow th, a process called metastasis
4. Both primary and secondary tumors require angiogenesis, the recruitment of new blood vessels, in order to grow to a large mass.
5. Cancer cells, which are closer in their properties to stem cells than to more mature differentiated cell types, usually arise from stem cells and other proliferating cells
Cancer Cells Have Escaped Cell Cycle Controls
• Cancer cells do not exhibit density dependent inhibition.
• Cancer cells do not stop growing when growth factor is depleted.
• Cancer cells stop at random points in cell cycle (not checkpoints).
• Some cancer cell lines are immortal and can divide indefinitely given the right
ingredients.e.g. HeLa cells.
• p53 gene mutations in tumor suppressor genes (e.g. p53) result in cancer functional
p53 aids cell in checkpoint control at G1 and G2
He La cells are human cancer cells of a patient Henrietta Lack; maintained in
tissue culture since 1953. They divide and double their number in every 24 hrs &
widely used in research.
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