What is Cancer? -- Quiz 1 Flashcards
What two properties are cancer cells defined by?
- Unregulated cell proliferation
- Invasion of other sites in the body
Tumor Definition
- An abnormal growth of cells that proliferate out of control Gove rise to a tumor
What two things can tumors be?
- Benign
- Malignant
Benign definition
does not invade surrounding tissues or metastasize
Malignant definition
capable of invading surrounding tissue and of metastasizing to secondary locations
What two things could either b benign to malignant?
- Neoplasm
- Neoplastic
What are some examples of tissue changes that are not cancer but are monitored because they could become cancerous?
- Carcinoma in situ
- Hyperplasia
- Dysplasia
What is a true cancer?
A tumor is considered a true cancer only if it is malignant.
What is Invasion?
The spread of tumor cells into surrounding tissue
What is Metastasis?
The process of cancer cells spreading from a primary site to secondary sites in the body.
What does cancer result from?
Cancer from the accumulation of genetic and epigenetic alterations in DNA
What are “cancer causing genes”?
Mutant alleles of genes that are required by cells for normal processes such as development and wound healing.
How do mutant alleles come about?
They are usually acquired by mutations caused by replication error and exposure to carcinogens
What causes genetic change?
- Heredity
- UV Radiation
- Chemicals
- Viruses
- Smoking
- Cells Dividing
What is a carcinogen?
a substance or agent that causes cancer
What is Carcinogenesis?
a multistep process that usually occurs over time as we accumulate mutations.
What is the biggest risk factor in cancer?
Aging
What are Driver Mutations?
- Mutations that have a causative role in tumor formation. (Drivers of cancer)
- Creates an allele of a gene that is advantageous for the cell that contains it.
- Results in clonal expansion of mutant alleles
What are Passenger Mutations?
- Mutations that occur in the same cell as the driver mutation but are not relevant to the tumor’s formation
- Occur due to genetic instability
- They do not confer a selective advantage
Clonal origin of cancer
- cancer arises from a single cell proliferation and invasion
Tumor Heterogeneity
Heterogenous due to high mutation rate, clonal diversification & microevolution
