patho2 exam 1 : Biology of cancer

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Questions and Answers

What is a major difference between pancreatic/ovarian cancer and breast/prostate cancer in terms of incidence and mortality?

The former has a lower incidence, but a higher mortality rate (correct)

There is no significant difference in incidence and mortality rates

Breast and prostate cancers are more lethal than pancreatic and ovarian cancers

The former has a higher incidence, but lower mortality rate

What is a key aspect of the majority of cancers?

They are a result of environmental factors only

They are caused by somatic mutations (correct)

They are heritable cancer syndromes

They are entirely preventable

What is a hallmark of cancer that enables tumor progression?

Activating invasion and metastasis

Tumor-promoting inflammation

Enabling replicative immortality (correct)

Deregulating cellular energetics

What is the term used to describe the process by which cancer cells evade the immune system?

Avoiding immune destruction Signup and view all the answers

What is the term used to describe the genetic changes that occur in cancer cells?

All of the above Signup and view all the answers

What is the term used to describe the process by which cancer cells acquire a blood supply?

Inducing angiogenesis Signup and view all the answers

What is the term used to describe the process by which cancer cells resist cell death?

Resisting cell death Signup and view all the answers

How many hallmarks of cancer are currently recognized?

8 Signup and view all the answers

What is the primary hallmark of cancer?

Uncontrolled cellular proliferation Signup and view all the answers

What is the function of proto-oncogenes in normal cells?

To ensure checkpoints are followed Signup and view all the answers

What is the result of the Philadelphia Chromosome translocation?

Production of a novel protein with growth-promoting properties Signup and view all the answers

How do oncogenes affect normal cell proliferation?

They stimulate cell growth independently of normal regulatory mechanisms Signup and view all the answers

What is the function of the G1 checkpoint?

To check for sufficient resources Signup and view all the answers

What is the result of the t(8;14) translocation in B lymphocytes?

Excess production of a proliferative factor Signup and view all the answers

How do some cancers secrete growth factors?

Through the activation of oncogenes Signup and view all the answers

What is the target of the drug Imatinib?

The BRC-ABL fusion protein Signup and view all the answers

What is the function of the S checkpoint?

To check DNA for errors Signup and view all the answers

What is the result of HPV infection in relation to cervical cancer?

Increased risk of cervical cancer Signup and view all the answers

What is the primary function of tumor suppressor genes in normal cells?

To regulate the cell cycle and inhibit proliferation Signup and view all the answers

What is the result of a mutation in the RB gene?

Less regulation on cell growth Signup and view all the answers

What is the role of p53 in DNA transcription?

To allow DNA transcription when DNA is normal Signup and view all the answers

What is the consequence of a single mutation in a germline cell?

Transmission of a cancer-causing gene to the next generation Signup and view all the answers

What is the result of inactivating both copies of a tumor suppressor gene?

Uncontrolled cell growth Signup and view all the answers

What is the function of contact inhibition in normal cells?

To stop cell division when surrounded by other cells Signup and view all the answers

What is the function of HIF-1α in angiogenesis?

To promote angiogenesis Signup and view all the answers

What is the characteristic of cancer cells regarding contact inhibition?

They do not exhibit contact inhibition Signup and view all the answers

What is the importance of angiogenesis in cancer?

It delivers oxygen and nutrients to the tumor Signup and view all the answers

What is the consequence of a mutated p53 gene?

Cell growth is unregulated Signup and view all the answers

Why are areas with rapidly renewing/dividing cells more sensitive to radiation?

Because they have higher cell turnover rates Signup and view all the answers

What is a key goal of targeted cancer therapy?

To directly interfere with a specific class of tumor's growth characteristics Signup and view all the answers

How do monoclonal antibodies, such as rituximab, work in cancer treatment?

By targeting unique antigens on cancer cells Signup and view all the answers

What is a characteristic of benign tumors?

Well demarcated with a capsule Signup and view all the answers

What is the term used to describe a malignant tumor?

Cancer Signup and view all the answers

How do cancer cells often accumulate genetic mutations?

Incrementally, over time Signup and view all the answers

What is a goal of chemotherapy in cancer treatment?

To limit the toxicity of any single agent Signup and view all the answers

Why are combinations of chemotherapy drugs often used?

To attack a cancer from many different weaknesses Signup and view all the answers

What is a characteristic of malignant tumors?

Poorly differentiated with anaplasia Signup and view all the answers

What is the role of immunotherapy in cancer treatment?

To stimulate the immune system to attack cancer cells Signup and view all the answers

What is the role of p53 in cancer?

To regulate tumor suppressor genes Signup and view all the answers

What is the result of increased HIF-1α in cancer cells?

Increased resistance to chemotherapy Signup and view all the answers

What is the function of VEGF in cancer?

To stimulate vascular endothelial growth Signup and view all the answers

Why are angiogenesis inhibitors not activated in cancer cells?

Due to p53 suppression Signup and view all the answers

What is the hallmark of cancer characterized by resisting cell death?

Apoptosis Signup and view all the answers

What is the intrinsic pathway of apoptosis?

Monitored for abnormal physiology Signup and view all the answers

What is the purpose of tumor markers in cancer diagnosis?

To identify individuals at high risk for cancer Signup and view all the answers

Why is PSA not used as a definitive diagnostic test for prostate cancer?

Due to high false-positive rates Signup and view all the answers

What is the purpose of surgery in cancer treatment?

To obtain tissue for diagnosis Signup and view all the answers

What is the goal of radiation therapy in cancer treatment?

To kill cancer cells while minimizing damage to normal structures Signup and view all the answers

What is the primary site of dysplasia occurrence?

Mouth mucosa and tongue Signup and view all the answers

What is the key difference between carcinoma in situ and invasive carcinoma?

Penetration of the basement membrane Signup and view all the answers

What is the significance of carcinoma in situ?

It is a significant risk factor for invasive cancer Signup and view all the answers

What is the difference between a pap smear and a biopsy?

Pap smear is a cytology specimen, biopsy is a histology specimen Signup and view all the answers

What is the term used to describe the progression from dysplasia to carcinoma in situ?

Neoplasia Signup and view all the answers

What are the possible fates of carcinoma in situ?

Progress to invasive cancer, remain stable, or regress Signup and view all the answers

What is the term used to describe the histologic features of malignancy that invade past the basement membrane?

Invasive carcinoma Signup and view all the answers

What is the term used to describe the filling of the mammary ducts with cancer cells, but without local tissue invasion?

Ductal Carcinoma In situ (DCIS) Signup and view all the answers

Study Notes

Cancer Incidence and Overview

Cancer incidence in the US: pancreas and ovary have lower incidence, but a higher percentage of deaths among those who develop these cancers
Breast and prostate cancers are more survivable than lung and bronchus cancers
Cancer is a disease caused by uncontrolled division of abnormal cells in a part of the body
Cancer is a collection of more than 100 different diseases, each caused by a specific and often unique age-related accumulation of genetic and epigenetic alterations

Inheritance of Cancer

There are heritable cancer syndromes
The majority of cancers are not familial
Cancer is a genetic disease, but the majority of mutations that lead to cancer are somatic (i.e., they happen in body cells, not in germ cells)

Hallmarks of Cancer

8 Hallmarks and 2 traits that enable cancer progression
The hallmarks of cancer include:
- Avoiding immune destruction
- Sustaining proliferative signaling
- Deregulating cellular energetics
- Resisting cell death
- Inducing angiogenesis
- Genomic instability (mutator phenotype)
- Activating invasion and metastasis
- Tumor-promoting inflammation
- Enabling replicative immortality
- Evading growth suppressors

Causes of Genetic Mutations

Viruses (e.g., HPV increasing risk of cervical cancer)
Bacteria (e.g., chronic H. pylori increasing risk for gastric adenocarcinoma)
Chemicals (e.g., smoking increasing risk for lung cancer)
Radiation (e.g., UV and ionizing radiation increasing risk of skin cancer)

Multiple Hits Lead to Cancer

Exposure, infection, or mutation can render a "hit"
Sometimes, one exposure can render just "half a hit"
Sometimes, a single exposure can pack two "hits" within it
Some people are born with one or more "pre-existing hits"

Sustained Proliferative Signaling

First and foremost, hallmark of cancer is uncontrolled cellular proliferation
Cancer cells do not obey or require normal signals for cell division
Cancer cells have the ability to divide indefinitely

Cell Division

Checkpoints are found at G1, S, and M (in Metaphase of M)
G1 checkpoint: cell checks that DNA is undamaged and resources are available
S checkpoint: checks DNA for errors
M checkpoint: checks that all sister chromatids are attached to mitotic spindles

Proto-oncogenes and Oncogenes

Proto-oncogenes are genes that encode components of pathways that regulate normal cell proliferation
Oncogenes are mutated or overexpressed proto-oncogenes
Oncogenes are independent of normal regulatory mechanisms
Example: HER2/neu gene, which encodes for a growth factor receptor

Translocation Mutations

Can activate oncogenes in two ways:
- Causing an excess production of a proliferative factor
- Leading to production of novel proteins with growth-promoting properties
Example: t(8;14) translocation leading to Burkitt Lymphoma

Tumor-Suppressor Genes

Jobs: normally regulate the cell cycle, inhibit proliferation from growth signals, stop cell division when cells are damaged, and prevent mutations
In cancer: oncogenes are activated and tumor suppressor genes are inactivated
Examples: Rb and p53 genes

Evading Growth Suppressors

Tumor-suppressor genes, such as RB, monitor antigrowth cellular signals and block activation of the growth/division phase in the cell cycle
Mutations in RB lead to persistent cell growth

Inducing Angiogenesis

Angiogenesis is the process of establishing new blood vessels
Importance of blood supply for the growth and spread of cancer
Example: VEGF (vascular endothelial growth factor)

Resisting Cell Death

Apoptosis: programmed cell death
Mechanism by which cells can self-destruct if needed during tissue remodeling or to protect against abnormal cell growth
Two pathways to apoptosis: intrinsic and extrinsic

Tumor Markers

Substances produced by both benign and malignant cells
Examples: hormones, enzymes, genes, antigens, and antibodies
Uses: screening, diagnosis, and following the clinical course of a tumor

Cancer Treatments

Surgery: allows us to obtain tissue for diagnosis and staging of disease
Radiation therapy: used to kill cancer cells while minimizing damage to normal structures
Chemotherapy: attacks rapidly dividing cells
Immunotherapy: emerging cancer treatment area
Targeted disruption of cancer: designed to address unique growth characteristics of a specific class of tumor

Tissue Pathology of Cancer

Definitions: neoplasm/tumor, malignant, benign, and cancer
Characteristics of benign and malignant tumors
Cancer classification: based on tissue and organ of origin, extent of distribution, microscopic appearance, and critical genetic changes

Progression to Malignancy

Cancers develop incrementally as they accumulate genetic mutations
Dysplasia: a premalignant condition
Carcinoma in situ (CIS): preinvasive epithelial tumors
Three fates: remain stable, progress to invasion or metastasis, or regress or disappear

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