BIOL 465 (Biology of Cancer) Flashcards
(118 cards)
What is aneuploidy?
A state of deviation from the normal (euploid) karyotype, as seen in many cancer cells.
What is a cell clone?
Any of the mutant cells directly descended from a single progenitor cell in which the mutation originally occurred.
What is chromosomal translocation?
A form of aneuploidy in which a segment is broken off from one chromosomal arm and becomes fused to the arm of another chromosome.
What is a double minute (DM)?
A subchromosomal fragment resulting from a form of aneuploidy in which a segment is cleaved out of a chromosome, replicates as an autonomous, extrachromosomal entity, and increases to many copies per nucleus.
What is euploidy?
The state in which chromosomes are configured normally, with autosomes present in normally structured pairs and X and Y chromosomes present in the numbers appropriate for the sex of the individual carrying them.
What are genetic polymorphisms?
The inter-individual, functionally silent differences in DNA sequence that make each human genome unique.
What is a homogeneously staining region (HSR)?
A form of aneuploidy in which a segment of a chromosome is copied many times over, with the resulting extra copies fused head-to-tail in long arrays within a chromosomal segment.
What is interstitial deletion?
A type of genetic mutation in which a segment in the middle of a chromosome is discarded and the flanking chromosomal regions are joined together.
What is a neutral mutation?
A mutation resulting in an allele that is phenotypically silent; neither advantageous nor disadvantageous.
What is reciprocal chromosomal translocation?
A form of aneuploidy in which chromosomal segments are exchanged between chromosomes from different chromosome pairs.
What are 6 major types of aneuploidy often seen in cancer cells?
- Accumulation of extra copies of otherwise normal chromosomes
- Translocation (reciprocal or not)
- HSRs
- DMs
- Gene amplification
- Deletion of growth-inhibiting genes
What is gene amplification?
An increase in the number of copies of genes carried in abnormal chromosomal segments, as seen in double minutes (DMs) and homogeneously staining regions (HSRs).
Which 2 major forms of aneuploidy result in gene amplification?
- Homogeneously staining regions (HSRs)
- Double minutes (DMs)
What condition must be met for a recently created mutant allele to be passed from an organism to its offspring?
The mutation must strike a gene carried in the genome of the sperm or egg, or in the genome of one of the cell types that are the immediate precursors of the sperm or egg within the gonads.
Approximately how many genes are in the human genome?
~22,000.
What are the two main broad classes of genes within mammalian cells?
- Housekeeping genes
- Tissue-specific genes
What are housekeeping genes?
Commonly expressed genes encoding proteins that are required universally to maintaing viability of all cell types or to carry out certain biological functions common to all cell types throughout the body.
What are tissue-specific genes?
Genes dedicated to the production of proteins (phenotypes) that are associated specifically with a differentiated cell.
What is pleiotropy?
The ability of a single transcription factor (or a single gene that specifies it) to elicit multiple changes within a cell or organism.
How can a malfunctioning pleotropic transcription factor lead to cancer?
It can simultaneously affect the expression of a large cohort of responder genes that together proceed to create the cancer cell phenotype.
What is a gene expression program?
The coordinated expression of multiple genes within a cell, dependent on the actions of multiple transcription factors acting in combination on large numbers of gene promoters.
What are the two broad categories of tumour, based on degree of aggressive growth?
- Benign
- Malignant
What is a benign tumour?
A tumour that grows locally without invading adjacent tissues.
What is a malignant tumour?
A tumour that invades nearby tissues and spawns metastases.