Cancer Notes from A.P. Biology

Neoplasm- abnormal growth of cells
-benign vs. malignant

Cancer- cellular growth disorder resulting from a mutation in genes that regulate the cell cycle

Carcinogenesis- development of cancer
-gradual process (possibly decades)

Characteristics of Cancer Cells

1. cancer cells lack differentiation
2. cancer cells have abnormal nuclei
-abnormal # of chromosomes
-mutated chromosomes (duplicated sections or deleted sections)
-amplification of specific genes
-no apoptosis

3. cancer cells form tumors
-no contact inhibition

4. cancer cells undergo metastasis and angiogenesis
-cancer in situ- tumor in place of origin
-metastasis- spreading
-angiogenesis- formation of new blood vessels (nutrients & oxygen)
*some treatment aimed at prevention of this

Origin of Cancer

Mutations take place where?
-enzymes that proofread DNA replication
-proto-oncogenes- directly or indirectly promote cell cycles
-tumor suppressor genes- directly or indirectly inhibit cell cycle
-telomers- regular shortening inhibited by telomerase

Regulation of Cell Cycle
-proto-oncogenes are end products of a stimulatory pathway starting with growth factors (proteins) entering through the cell membrane to get the ball rolling. (sort to speak) (ex. make cyclins)
*promote cell cycle

-tumor suppressor genes are at the start of inhibitory pathway
*inhibit cell cycle

-together, proto-oncogenes and tumor suppressor genes make up a system of checks and balances for control of cell cycle

-mutations in proto-oncogenes cause the to be oncogenes (cancer-causing genes)

-mutations in tumor suppressor genes cause cell cycle to proceed uncheckcd
*6 tumor suppressor genes
*RB tumor suppressor gene
+malfunctions in breast, prostate, bladder cancer
+loss of gene leads to small-cell lung carcinoma
+mutated RB gene leads to eye tumors by age 3

*p53 tomor suppressor gene
+most frequently mutated gene in human cancers (1/2)
+turns on gene whose products are cell cycle inhibitors
+also stimulates apoptosis

Misty thanks all the notes will help people out.

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