30 Questions
Which type of recurrent rearrangement involves a segment being reversed end to end?
Inversion
Which mechanism of oncogene activation involves the formation of novel hybrid fusion genes?
De regulated expression of oncogenes via regulatory control of an immunoglobulin gene
What is the most important tumor suppressor gene?
TP53
Which mutation type can TP53 gene have?
All of the above
Which of the following best describes the concept of carcinogenesis?
Carcinogenesis is a multi-step process that involves genetic and epigenetic changes in cellular division and regulation.
Which of the following best describes the function of oncogenes?
Oncogenes are genes that promote tumor growth.
Which of the following best describes Knudson's Two-Hit Hypothesis?
Knudson's Two-Hit Hypothesis explains the function of tumour suppressor genes.
According to the text, what is the definition of cancer?
A disease of multicellular organisms characterized by abnormal proliferation of cells and invasion of local tissue
What are the two main types of cancer-associated genes mentioned in the text?
Proto-oncogenes and tumour suppressor genes
According to the text, what is the process by which normal cells are transformed into cancer cells called?
Carcinogenesis
Which of the following is NOT mentioned as an environmental factor that can lead to genetic changes and cause cancer to develop?
Diet and Exercise
Which technique is used to detect amplification of the c-myc gene in double minutes (dmins)?
Interphase FISH
Which gene is amplified in double minutes (dmins) in the AML patient in Case 2?
KMT2A
Which type of chromosomal rearrangement is often detected in haematological malignancies and some solid tumors?
Interchromosomal translocations
Which mechanism of oncogene activation involves the formation of novel hybrid fusion genes with transforming activity?
Formation of novel hybrid fusion genes
Which theory suggests that carcinogenic agents disrupt interactions between cells that maintain tissue architecture, repair, and regulation?
Tissue Organization Field Theory (TOFT)
According to Knudson's Two-Hit Hypothesis, what is true about the recessive nature of tumor suppressor genes?
Tumor suppressor genes are recessive in nature
Which process involves multiple mutations and is a characteristic of carcinogenesis?
Multi-step process
Which type of genes are involved in regulating cell growth and differentiation, and have the potential to become oncogenes?
Proto-oncogenes
Which of the following is NOT a mechanism of oncogene activation?
DNA mismatch-repair
What is the function of DNA mismatch-repair genes?
To recognize and repair errors during replication and recombination
Which of the following is NOT one of the hallmarks of cancer?
Inducing apoptosis
How can cancer cells resist apoptosis?
Mutation/loss of TP53
Which of the following is a characteristic of cells that have bypassed replicative immortality?
Overexpression of BCL-2
Which of the following is a hallmark of cancer?
Enabling replicative immortality
What is the function of telomeres?
To protect the ends of chromosomes
Which of the following is NOT a mechanism of oncogene activation?
Deletions
Which type of mutation involves the alteration of a single nucleotide in the DNA sequence?
Point mutations
What is the result of gene amplification?
Increased gene expression
Which gene is commonly amplified in small-cell lung cancer, breast/ovarian cancer, and leukemias?
c-myc
Study Notes
Recurrent Rearrangements and Oncogene Activation
- Inversion involves a segment being reversed end to end.
- The formation of novel hybrid fusion genes is a mechanism of oncogene activation.
- Oncogenes are involved in regulating cell growth and differentiation and have the potential to become oncogenes.
Tumor Suppressor Genes and Cancer
- TP53 is the most important tumor suppressor gene.
- TP53 can have missense mutations.
- Cancer is defined as a disease characterized by the uncontrolled growth and spread of abnormal cells.
- The two main types of cancer-associated genes are oncogenes and tumor suppressor genes.
- Carcinogenesis is the process by which normal cells are transformed into cancer cells.
Environmental Factors and Genetic Changes
- Environmental factors, except for aging, can lead to genetic changes and cause cancer to develop.
- DNA mismatch-repair genes are involved in the repair of DNA damage.
Chromosomal Rearrangements and Cancer
- Translocation is a type of chromosomal rearrangement often detected in haematological malignancies and some solid tumors.
- Amplification of the c-myc gene in double minutes (dmins) is detected using fluorescence in situ hybridization (FISH) technique.
- The c-myc gene is amplified in double minutes (dmins) in the AML patient in Case 2.
Knudson's Two-Hit Hypothesis and Oncogene Activation
- Knudson's Two-Hit Hypothesis suggests that tumor suppressor genes are recessive in nature.
- The formation of novel hybrid fusion genes with transforming activity is a mechanism of oncogene activation.
Cancer Characteristics and Hallmarks
- Carcinogenesis involves multiple mutations.
- Telomeres are involved in the maintenance of chromosomal integrity.
- Cancer cells can resist apoptosis through various mechanisms.
- Cells that have bypassed replicative immortality have a characteristic of uncontrolled growth.
- Self-sufficiency in growth signals, insensitivity to anti-growth signals, and evasion of apoptosis are hallmarks of cancer.
- Genetic instability and mutation are hallmarks of cancer.
- Gene amplification results in the increase of gene copy number and expression.
Mutation Types and Gene Function
- Point mutation involves the alteration of a single nucleotide in the DNA sequence.
- HER2 gene is commonly amplified in small-cell lung cancer, breast/ovarian cancer, and leukemias.
Test your knowledge on the mechanisms of oncogene activation and DNA mismatch-repair genes. Learn about the different ways oncogenes can be activated and the role of DNA mismatch-repair genes in maintaining genomic stability.
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