MEDSURG I FINAL EXAM
CANCER (21)
Biology of cancer : difference b/w proliferation and differentiation
o Normal cells
Proliferation
• Stem cells-mature cells
-stem cells have their own process
-time is differen
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MEDSURG I FINAL EXAM
CANCER (21)
Biology of cancer : difference b/w proliferation and differentiation
o Normal cells
Proliferation
• Stem cells-mature cells
-stem cells have their own process
-time is different
• Cellular division
• Contact inhibition
Differentiation
• Protooncogenes
• Tumor Suppressor genes
• The divided cells are identical to parent cells.
• The functional in the same way as parent cells.
o Cancer cells
Defects in Proliferation
• Proliferation is indiscriminate and continuous.
• Producing more cells than normal.
• No contact inhibition (can invade other organs and spaces)
Defects in Differentiation
• Mutation• Proteins th
at change the cellular structure.
• Lack of proper transfer of genetic information.
Genes that can be affected by mutation
o Protooncogenes
When this lock is “unlocked,” as may occur through exposure to carcinogens or
oncogenic viruses, genetic alterations and mutations occur.
• For example, some cancer cells produce new proteins, such as those
characteristic of the embryonic and fetal periods of life. These proteins, located on
the cell membrane, include carcinoembryonic antigen (CEA) and α-fetoprotein (FP).
o Tumor suppressor genes
Mutations render them inactive.
Result in loss of suppression of tumor growth
• Examples of tumor suppressor genes are BRCA-1 and BRCA-2.
• Another tumor suppressor gene is the APC gene. Alterations in this gene increase
a person’s risk for familial adenomatous polyposis, which is a precursor for colorectal
cancer.
Development of cancer
o 1.Initiation
Mutation of cell’s genetic structure (exposure to chemicals radiation or viral)
• From inherited mutation or exposure to chemical, radiation, viral agent
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