Chapter 18.5 Flashcards
Cancer results from
genetic changes that affect cell cycle control
The gene regulation systems that go wrong during cancer are the very same systems involved in
embryonic development
Cancer can be caused by
mutations to genes that regulate cell growth and division
Tumor viruses can cause cancer in
animals including humans
Oncogenes are
cancer-causing genes.
bad genes. don’t want oncogenes
Proto-oncogenes are
the corresponding normal cellular genes that are responsible for normal cell grown and division.
(good genes)
Conversion of a proto-oncogene to an oncogene can lead to
abnormal stimulation of the cell cycle, (then they divide a lot and turn into cancer)
Tumor-suppressor genes help
prevent uncontrolled cell growth
good genes. they stop us from having tumors
Mutations that decrease protein products of tumor-suppressor genes may contribute to
cancer onset
Tumor-suppressor proteins
- Repair damaged DNA
- Control cell adhesion
- Inhibit the cell cycle in the cell-signaling pathway
Mutations in the ras proto-oncogene and p53 tumor-suppressor gene are
common in human cancers
Mutations in the ras gene can lead to
production of a hyperactive Ras protein and increased cell division
Suppression of the cell cycle can be important in the case of
damage to a cell’s DNA; p53 prevents a cell from passing on mutations due to DNA damage
Mutations in the p53 gene prevent
suppression of the cell cycle
ras
proto-oncogene ((and oncogene??))
p53
tumor-suppressor gene
Multistep mutations are generally needed for
full-fledged cancer; thus the incidence increases with age
At the DNA level, a cancerous cell is usually
characterized by at least one active oncogene and the mutation of several tumor-suppressor genes
Individuals can inherit
oncogenes or mutant alleles of tumor-suppressor genes
Inherited mutations in the tumor-suppressor gene adenomatous polyposis coli are
common in individuals with colorectal cancer
Mutations in the BRCA1 or BRCA2 genes are found in at least
half of inherited breast cancers, and tests using DNA sequencing can detect these mutations
