Download Lecture 35 POWERPOINT here

CANCER
General
• A general grouping of all diseases related to
unregulated cell growth
• Cancers generally develop by an
accumulation of mutations of the DNA
• Begin at the DNA level
Multi-hit hypothesis
• All cancers appear to be the result of multiple
DNA damage events
• Each event causes that cell, and its
descendents, to lose more and more control
over the cell cycle
• Eventually, a tumor may form
• Then, if the cancer begins to leave, survive,
and populate other regions of the body, we
have metastasis - the growth of the tumor in
other regions - this is cancer!
DNA damage
•
Number of forms can lead to cancer
1. Direct changes to the DNA
1. Point mutations
2. Insertions and Deletions
2. Relocation of DNA
1. Translocation of chromosomes
2. Loss of chromosomes
3. Duplication of chromosomes
3. Viral and Transposon agents
1. Viruses can insert into critical genes
2. So may transposones
Two mechanisms of action - 1) disruption of function, as shown
here, or 2) disruption of homeostasis - bone cancer and Ca2+
21_42_metastasis.jpg
21_43_Cancer_chromos.jpg
21_44_Tumors.jpg
Common feature of cancer cells
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Reduced dependence of extracellular signals
Less likely to undergo apoptosis
Unregulated cell division
Unstable - high mutation rate
Invasive - they lack cell-adhesion molecules
Survive in foreign tissues
21_45_proto_oncogenes.jpg
21_46_oncogene.jpg
21_47_cancer_pathways.jpg
21_48_Colorectal_cancer.jpg
21_49_APC_gene_mutat.jpg
21_50_APC_Wnt.jpg
21_51_tumor_cells.jpg
21_52_Gleevec.jpg
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