Cancer Biology Quiz

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Questions and Answers

What characteristic distinguishes benign tumors from malignant tumors?

They are always lethal to patients.

They are derived from the Latin word for 'crab'.

They remain localized and do not metastasize. (correct)

They always invade adjacent tissues.

Which term describes the process by which cancer cells spread to distant sites?

Invasion

Metastasis (correct)

Initiation

Promotion

What step in multistep carcinogenesis involves a permanent change in DNA?

Promotion

Malignancy

Progression

Initiation (correct)

Which of the following is NOT considered a tumor promoter in cancer development?

Stress Signup and view all the answers

What is the primary feature of malignant tumors compared to benign tumors?

They can cause significant morbidity and are harder to manage. Signup and view all the answers

Which phase of carcinogenesis involves the acquisition of additional mutations leading to invasive cancer?

Progression Signup and view all the answers

During which process do abnormal cancer cells invade neighboring tissues?

Invasion Signup and view all the answers

What is the definition of metastasis in the context of cancer?

The release of cancer cells into the bloodstream to form secondary tumors. Signup and view all the answers

Which virus is primarily linked to cervical cancer?

Human papillomavirus Signup and view all the answers

What is a significant non-modifiable risk factor for cancer?

Age Signup and view all the answers

Which of the following is a characteristic of a weakened immune system related to cancer risk?

Greater susceptibility to some types of cancer Signup and view all the answers

What concept was introduced by Douglas Hanahan and Robert Weinberg in their paper published in 2000?

The hallmarks of cancer Signup and view all the answers

What commonly misunderstood aspect relates to carcinogens?

They can also affect genetic mutations Signup and view all the answers

Which of the following bacterial infections is associated with an increased risk of stomach cancer?

Helicobacter pylori Signup and view all the answers

Which statement about genetic predisposition to cancer is true?

It increases the likelihood of specific types of cancer Signup and view all the answers

Which of the following best describes the expanded understanding of cancer hallmarks since 2000?

They have been increased to eight capabilities and two enabling capabilities Signup and view all the answers

What is primarily responsible for the self-sufficiency in growth signals in tumors?

Gain-of-function mutations in proto-oncogenes Signup and view all the answers

Which hallmark characteristic is NOT one of the original hallmarks of cancer as proposed by Weinberg and Hanahan?

Abnormal metabolic pathways Signup and view all the answers

How does RAS contribute to tumor growth according to the content?

By blocking hydrolysis of GTP to GDP Signup and view all the answers

In what way do the recruited normal cells in a tumor contribute to cancer?

They create a conducive tumor microenvironment. Signup and view all the answers

Which function does inflammation NOT serve in the context of the hallmarks of cancer?

Facilitating apoptosis of cancer cells Signup and view all the answers

Which is NOT considered one of the enabling characteristics of cancer?

Genome stability Signup and view all the answers

Which component plays a critical role in the activation of signal transduction pathways downstream of growth factor receptors?

GTP-binding proteins Signup and view all the answers

What effect does genome instability have on cancer cells?

It enhances the acquisition of hallmark traits. Signup and view all the answers

Which diagnostic method is primarily used for the detection of cervical carcinoma?

Cytopathological examination Signup and view all the answers

What does immunohistochemistry primarily help determine about a tumor?

Specific proteins and tumor nature Signup and view all the answers

Which cytological method is most commonly used with palpable lesions such as the breast or lymph nodes?

Fine-needle aspiration cytology Signup and view all the answers

What type of biopsy involves the removal of a small tissue sample for examination?

Needle biopsy Signup and view all the answers

What classification method is used routinely for leukemias and lymphomas?

Flow Cytometry Signup and view all the answers

Which of the following is NOT a benefit of using immunohistochemistry?

Providing genomic sequencing information Signup and view all the answers

Which tumor marker is specifically used to monitor prostate cancer?

Prostate-specific antigen (PSA) Signup and view all the answers

Which method uses spontaneously exfoliated cells for cancer detection?

Exfoliative cytology Signup and view all the answers

What molecular technique is used primarily to detect genetic changes and chromosomal abnormalities?

Fluorescence in situ hybridization (FISH) Signup and view all the answers

In histopathological examination, what is typically obtained for diagnosis?

Tissue samples Signup and view all the answers

Which of the following is NOT a function of tumor markers?

Diagnose hereditary predisposition Signup and view all the answers

Which tumor marker is primarily associated with pancreatic cancer?

Carbohydrate antigen 19-9 (CA19-9) Signup and view all the answers

Which of the following molecular techniques is considered advanced for reading DNA quickly?

Next-generation sequencing (NGS) Signup and view all the answers

What is the role of tumor suppressor genes in cell cycle regulation?

They encode proteins that help repair DNA damage. Signup and view all the answers

Which of the following is a known carcinogen associated with adenocarcinoma of the lung?

Asbestos Signup and view all the answers

Which statement best describes the Warburg effect in cancer cells?

Cancer cells rely on lactic acid fermentation despite having oxygen. Signup and view all the answers

What is the main purpose of using tumor markers in cancer care?

To monitor and evaluate treatment effectiveness Signup and view all the answers

Which of the following statements about carcinogenesis is correct?

Carcinogenesis occurs in multiple steps. Signup and view all the answers

What happens when a DNA damaged cell attempts to divide?

Tumor suppressor proteins halt its proliferation. Signup and view all the answers

How do cancer cells typically alter their metabolism for growth?

They prefer lactic acid fermentation even with oxygen available. Signup and view all the answers

What is a key characteristic of the intrinsic pathway of apoptosis in cancer cells?

Progression through the intrinsic pathway is often disrupted. Signup and view all the answers

What is the primary consequence of the inactivation of tumor suppressor genes in cancer?

Uncontrolled proliferation of mutated cells. Signup and view all the answers

Which tumor suppressor gene is commonly known as the 'Guardian of the genome'?

p53 gene Signup and view all the answers

What is the main role of second messengers in signal transduction?

To transmit signals from receptors to nuclear regulatory factors. Signup and view all the answers

What phase of the cell cycle involves both chromosome duplication and preparation for mitosis?

S phase Signup and view all the answers

Which phase of the cell cycle is the shortest in duration?

M phase Signup and view all the answers

During which phase of the cell cycle does a cell double in size?

G1 phase Signup and view all the answers

Which of the following correctly describes interphase?

The longest stage of the cell cycle Signup and view all the answers

What is the primary activity that occurs during G2 phase of the cell cycle?

Preparation for mitosis Signup and view all the answers

What significant event occurs during the M phase of the cell cycle?

Chromosome segregation takes place Signup and view all the answers

Which statement about the S phase is true?

DNA is synthesized during this phase Signup and view all the answers

What is primarily synthesized during the G1 phase of the cell cycle?

RNA and proteins Signup and view all the answers

What is a consequence of mutations in the p53 tumor suppressor gene?

Decreased apoptosis rates in cells Signup and view all the answers

Which statement accurately describes Rb in the context of cancer?

Rb is classified as a tumor suppressor gene. Signup and view all the answers

How do RAS mutations influence cell proliferation?

They lead to overactive cell signaling pathways. Signup and view all the answers

What role does p53 play concerning cellular stress and potential cancer development?

It coordinates DNA repair and cell cycle arrest. Signup and view all the answers

Which of the following is a common characteristic of tumor suppressor genes like p53 and Rb?

They are involved in inhibiting cancerous cell formation. Signup and view all the answers

What is the primary role of the Rb protein in the cell cycle?

Inhibiting transcription of genes required for cell cycle progression Signup and view all the answers

According to Knudson's two-hit hypothesis, which of the following is true regarding retinoblastoma?

In inherited cases, the first mutation is typically inherited. Signup and view all the answers

What types of tumors are associated with mutations in the Rb gene?

Retinoblastoma and osteosarcoma Signup and view all the answers

Which statement best describes the nature of mutations in retinoblastoma?

Different types of mutations can lead to different forms of retinoblastoma. Signup and view all the answers

What is the impact of Rb protein on E2F proteins during the G1 phase?

Rb binds to E2F, inactivating its ability to drive the cell cycle. Signup and view all the answers

In non-inherited retinoblastoma, how many mutations must occur?

Two mutations are required for tumor development. Signup and view all the answers

What chromosome is the Rb gene located on?

Chromosome 13 Signup and view all the answers

Which phase of the cell cycle does the Rb protein primarily regulate?

G1 phase Signup and view all the answers

What triggers the conformational change in Ras that allows it to bind GTP?

Binding of extracellular signals to cell surface receptors Signup and view all the answers

What is the role of activated ERK in the cellular response to Ras activation?

Translocation to the nucleus to phosphorylate transcription factors Signup and view all the answers

Which of the following pathways is primarily initiated by active Ras proteins?

MAPK/ERK pathway Signup and view all the answers

How does Ras contribute to cell proliferation?

By stimulating the expression of genes that promote cell cycle progression Signup and view all the answers

What is the primary difference between GDP and GTP in the context of Ras activation?

GTP promotes a conformational change in Ras Signup and view all the answers

Which of the following best describes the classification of oncogenes related to Ras signaling?

Cytoplasmic signal transduction molecules, including Ras, are classified as oncogenes Signup and view all the answers

What is a major consequence of active Ras signaling in the context of gene regulation?

Transcriptional regulation leading to changes in gene expression Signup and view all the answers

Which signaling molecule is NOT directly activated by Ras in downstream signaling?

Caspase Signup and view all the answers

What is the primary decision made at the G1 phase of the cell cycle?

The cell enters the G0 phase or proceeds to S phase Signup and view all the answers

What characterizes the S phase in the cell cycle?

The DNA is replicated resulting in chromatids Signup and view all the answers

What is the role of the G2 checkpoint in the cell cycle?

To ensure DNA replication has occurred correctly Signup and view all the answers

What happens to the chromosomes during the S phase?

They are replicated, resulting in two sets of chromatids Signup and view all the answers

Which of the following describes the transition between the G1 phase and the S phase?

The cell commits to division at the restriction point Signup and view all the answers

What effect does point mutation in protein kinases like Src have on substrate specificity?

It broadens substrate specificity to include new mitogenic proteins. Signup and view all the answers

Which of the following statements about gene amplification is correct?

It is an increase in the number of gene copies, often resulting in overproduction of proteins. Signup and view all the answers

What key factor is checked at the G2 checkpoint to ensure the cell can proceed to mitosis?

Presence of mitosis promoting factor (MPF) Signup and view all the answers

What is the primary consequence of errors in DNA repair or chromosome segregation?

Changes in chromosome structure or number that increase gene copy number. Signup and view all the answers

In which phase are the original chromosomes and their duplicates connected at the centromere?

S phase Signup and view all the answers

How does the RAS gene primarily contribute to tumor development?

Through point mutations that activate signaling pathways. Signup and view all the answers

Which of the following statements best describes the G0 phase?

It allows some cells to exit the active cell cycle phase Signup and view all the answers

Which statement describes the function of GAPs in relation to Ras?

GAPs inactivate Ras by stimulating GTP hydrolysis. Signup and view all the answers

Which of the following cancers is most commonly associated with mutations in the RAS gene?

Cholangiocarcinoma. Signup and view all the answers

What results from the GDP-bound form of Ras?

It is in an inactive state preventing signal transduction. Signup and view all the answers

Which statement about GEFs in relation to Ras is accurate?

GEFs activate Ras by facilitating its exchange of GDP for GTP. Signup and view all the answers

Which cancers exhibit a substantially increased risk due to BRCA1 mutations?

Epithelial ovarian cancers and prostate cancer Signup and view all the answers

What is a common feature of ER-positive breast cancers?

Involvement of chromosomal gains and losses Signup and view all the answers

Which type of breast cancer is primarily associated with loss of BRCA1 function?

Basal-like tumors Signup and view all the answers

Which imaging test is useful for distinguishing solid masses from fluid-filled cysts?

Ultrasound Signup and view all the answers

What cellular consequence is associated with defective versions of BRCA1 and BRCA2 genes?

Development of chromosomal breaks and severe aneuploidy Signup and view all the answers

Which condition is NOT a precursor lesion for ER-positive cancers?

Atypical apocrine adenosis Signup and view all the answers

What is true regarding BRCA2 mutations?

Enhance risk for cancers in both genders Signup and view all the answers

What diagnostic method provides detailed images especially useful for high-risk breast cancer patients?

MRI Signup and view all the answers

What characterizes nonproliferative fibrocystic change in the breast?

It features localized dilatation of ducts and cyst formation. Signup and view all the answers

Which statement about fibroadenomas is true?

They usually present as solitary tumors detected during mammography. Signup and view all the answers

Which HPV types are primarily associated with the development of condylomas in the lower genital tract?

Types 6 and 11 Signup and view all the answers

What is the primary factor that influences the prognosis for invasive breast carcinoma?

The molecular characteristics of the carcinoma cells. Signup and view all the answers

Which type of carcinoma is a precursor lesion for ductal carcinoma?

Ductal carcinoma in situ. Signup and view all the answers

Which diagnostic procedure uses a magnifying instrument to examine abnormal areas of the cervix?

Colposcopy Signup and view all the answers

How do cystic changes in breast tissue typically arise?

Due to irregularities in response to menstrual cycle variations. Signup and view all the answers

What is the primary purpose of regular Pap Smears and HPV Testing in cervical cancer prevention?

To detect precancerous changes or infections early Signup and view all the answers

Which statement about lobular carcinomas is accurate?

They arise chiefly from the lobules of the breast. Signup and view all the answers

Which surgical procedure is aimed specifically at removing a cone-shaped section of abnormal cervical tissue?

Conization Signup and view all the answers

What type of therapy uses drugs that specifically target pathways utilized by cancer cells to promote growth?

Targeted Therapy Signup and view all the answers

What typically happens to nonproliferative fibrocystic changes after menopause?

They often recede. Signup and view all the answers

What type of breast carcinoma represents over 90% of cases and arises from the ducts?

Ductal carcinoma. Signup and view all the answers

Which prevention strategy is recommended to significantly reduce the risk of HPV infection?

HPV Vaccination Signup and view all the answers

What is the purpose of Endocervical Curettage in cervical diagnostics?

To scrape cells from the cervical canal Signup and view all the answers

What type of cancer treatment is often combined with chemotherapy to enhance the destruction of cancer cells?

Radiation Therapy Signup and view all the answers

What is the primary purpose of hormone receptor tests in cancer diagnosis?

To check if cancer cells have specific hormone receptors Signup and view all the answers

Which surgical procedure involves the removal of a tumor along with some surrounding tissue?

Lumpectomy Signup and view all the answers

What is the action of immunotherapy in cancer treatment?

To enhance the body's immune response against cancer cells Signup and view all the answers

Which of the following is NOT a common recommendation to reduce the risk of breast cancer?

Increased consumption of processed foods Signup and view all the answers

Which treatment specifically targets the HER2 protein in certain breast cancers?

Trastuzumab Signup and view all the answers

What is the main goal of neoadjuvant chemotherapy?

To shrink tumors before surgery Signup and view all the answers

What type of therapy is primarily intended for cancers that have metastasized to the bone?

Bone-directed therapy Signup and view all the answers

What is primarily responsible for the formation of neuritic plaques in Alzheimer's disease?

Deposits of β-amyloid fragments Signup and view all the answers

Which of the following is a key dietary recommendation for reducing breast cancer risk?

Eating a diet rich in fruits and vegetables Signup and view all the answers

Which enzyme is NOT involved in the cleavage of amyloid precursor protein (APP)?

δ-secretase Signup and view all the answers

What change occurs to tau protein in Alzheimer's disease?

It shifts to a somatic-dendritic distribution. Signup and view all the answers

What is the primary abnormality associated with Alzheimer’s disease?

Accumulation of β-amyloid and tau Signup and view all the answers

Which statement about neurofibrillary tangles in Alzheimer’s disease is correct?

They are aggregates of hyperphosphorylated tau protein. Signup and view all the answers

What is the consequence of tau protein losing its ability to bind to microtubules in Alzheimer's disease?

Formation of neurofibrillary tangles Signup and view all the answers

What is a secondary effect of the accumulation of plaques and tangles in Alzheimer's disease?

Neuron death and dysfunction Signup and view all the answers

Which protein does the amyloid precursor protein (APP) lead to the production of when cleaved by the appropriate enzymes?

β-amyloid Signup and view all the answers

What role does the E6 protein play in oncogenesis?

It binds to p53, leading to its degradation. Signup and view all the answers

Which consequence arises from the integration of the HPV genome into the host genome?

Overexpression of E6 and E7 oncoproteins. Signup and view all the answers

What characteristic distinguishes high-risk HPV types from low-risk types?

Increased affinity for p53 and RB proteins. Signup and view all the answers

How does the E7 protein contribute to tumorigenesis?

By displacing E2F transcription factors from RB. Signup and view all the answers

What is the primary consequence of the persistence of high-risk HPV types in infected individuals?

Increased risk of progression to cancer. Signup and view all the answers

Which factor is primarily linked to the pro-oncogenic mutations in host cancer genes?

Integration of the HPV genome into the host genome. Signup and view all the answers

Which types of HPV are primarily responsible for the majority of cervical carcinoma cases?

Types 16 and 18. Signup and view all the answers

What impact does HPV infection have on the host cell cycle regulation?

It accelerates progression through the G1-S checkpoint. Signup and view all the answers

Study Notes

BIOL 2006SEF - CELLS IN HEALTH AND DISEASE

Course topic: Cell Cycle and Cancer Development I
Instructor: Heidi Wong
Contact: [email protected]

Outline

Overview of Cancer
Causes and risk factors of cancer
Hallmarks of cancer
Laboratory Diagnosis of Cancer

Major Cause of Death in Hong Kong

Malignant neoplasms (ICD-10: C00-C97) are the leading cause of death in Hong Kong.
Pneumonia (ICD-10: J12-J18) is a significant cause of death, along with other diseases like those of the heart, cerebrovascular diseases, external causes, nephritis, and dementia.

Key Facts of Human Cancer

Over 200 types of cancers exist.
In well-developed countries, cancer accounts for approximately 20-30% of deaths.
Roughly one in three people will experience cancer treatment.
No single cure exists for all cancers.
Cancer incidence will likely increase with extended lifespans.
An estimated 10 million people die from cancer each year globally.
Approximately one-third of common cancers are preventable.
Cancer is the second leading cause of death worldwide.
Low-to-middle-income countries account for 70% of cancer deaths.
Prevention, early detection, and treatment could save millions of lives annually.
Top 10 cancers in Hong Kong (2020/21 data) include lung, colorectal, breast, prostate, liver, stomach, corpus uteri, thyroid, non-Hodgkin lymphoma, and pancreatic cancer.

What is Cancer?

Cancer arises from uncontrolled abnormal growth of normal cells forming a lump called a tumor; Leukemia is an exception.
Unchecked tumors can spread to surrounding normal tissue via bloodstream and lymphatic systems.
Can affect the digestive, nervous, and circulatory systems and potentially release hormones that impact bodily functions.

What is Tumor (Neoplasm)?

Neoplasia literally means "new growth."
Tumors can be benign or malignant (cancerous).
Benign tumors originate from epithelial or glandular tissues (carcinomas) in roughly 80-90% of cases.
Sarcomas arise from connective tissues, roughly in 5% of cases.
Malignant tumors originate from lymphatic cells (leukemia and lymphomas) in a smaller percentage (5-10%).

Benign vs. Malignant Tumors

Benign tumors are generally relatively harmless, remain localized, and are easily treatable with surgical removal. They may cause significant morbidity and even death in rare instances.
Malignant tumors, collectively called cancers, are aggressive and can invade neighboring tissues and spread to distant sites, a process called metastasis. This process can cause death.

Invasion & Metastasis

Abnormal cancer cells proliferate and spread to other parts of the body.
Invasion: Direct migration and penetration into neighboring tissues.
Metastasis: Cancer cells spread (metastasize) via lymphatic system and blood vessels.

Multistep Carcinogenesis

Initiation: Carcinogens (physical, chemical, or biological agents) trigger permanent DNA alterations.
Promotion: Initiated cells respond to growth stimuli, such as alcohol, dietary fat, etc.
Progression/Malignancy: Pre-neoplastic cells progressively acquire alterations resulting in malignancy.

The Main Steps in the Formation of a Metastasis

Primary tumor formation
Proliferation and angiogenesis
Detachment and invasion
Embolism and circulation
Transport and arrest in organs
Extravasation
Establishment of a microenvironment
Proliferation and angiogenesis

Metastasis

Metastasis is the process where cancer cells leave the primary tumor, travel to a distant site, and establish a secondary tumor through the circulatory system.
Vascularization is crucial for tumor growth.
Tumor cells invade the organ's stroma (connective tissue).
Cells spread through lymphatic and vascular channels
Tumors must navigate the circulatory system and resist the immune and non-immune systems.
Tumor cells must arrest in capillary beds of distant organs, extravasate into distant organs, and survive and proliferate in their new environment.
Metastasis is not random, driven by favorable conditions (the "seed and soil" hypothesis).

Metastasis in Not Random

The "seed and soil" hypothesis suggests metastasis is influenced by anatomical and hemodynamic factors of the vascular system, specific to certain organs.

Principles of the Seed and Soil Hypothesis

Tumors are biologically heterogeneous.
Metastasis is a selective process for cells with certain characteristics.
Metastasis success depends on interactions with the host organ's microenvironment.

Top 10 Cancers in Hong Kong (2020/21 Data)

Lung cancer, colorectal cancer, breast cancer, prostate cancer, liver cancer, stomach cancer, corpus uteri cancer, thyroid cancer, non-Hodgkin lymphoma, and pancreatic cancer were in the top 10.

Causes and Risk Factors of Cancer

Multiple factors cause cancer, often the result of several interacting risk factors.
Modifiable risk factors include excessive alcohol consumption, being overweight or obese, poor diet high in red meat, and inadequate physical activity.
Factors including tobacco smoke, ionizing radiation, workplace hazards, and infectious agents (like viruses) contribute.

Non-modifiable Risk Factors

Age (longer lifespan= greater exposure to carcinogens)
Cancer-causing substances (carcinogens) alter cell behavior, increasing cancer risk.
Genetics (predisposing factors, like BRCA genes)
Weakened immune systems increase cancer risk (organ transplant recipients, HIV/AIDS, etc).

IARC's Carcinogen Classifications

The International Agency for Research on Cancer (IARC) classifies substances into groups (1-4) based on evidence of carcinogenicity, with Group 1 representing the highest risk.

Hallmarks of Cancer

Set of properties imparted on cancer cells by genetic alterations (mutations, epigenetic).
Eight hallmark functions, with 2 enabling capabilities, now characterized in cancer cells.
Hanahan and Weinberg (paper "The Hallmarks of Cancer" published in 2000 in Cell, with a 2011 update).

Laboratory Diagnosis of Cancer

Cytopathological examinations like Pap smears detect cancer cells in body fluids.
Histological analysis of tissue samples (needle biopsies, endoscopic biopsies, excision biopsies).
Immunohistochemistry uses antibodies to identify specific proteins in tissue samples.
Flow cytometry is primarily used for classifying leukemias and lymphomas.
Tumor markers help monitor cancer progression and treatment efficacy.

Molecular Diagnosis

Molecular techniques like PCR, FISH, sequencing, and NGS analyze genetic changes in cells associated with cancer.
Used for diagnosing, assessing prognosis, detecting residual disease, determining predisposition to cancer, and guiding treatment decisions.

References

Vinay Kumar, Abul K. Abbas, Jon C. Aster, Andrea T. Deyrup. (2022). Robbins & Kumar Basic Pathology (11th ed.). Elsevier.
Hanahan D and Weinberg RA. (2000). The hallmarks of cancer. Cell. 100(1): 57-70.
Hanahan D and Weinberg RA. (2011). Hallmarks of Cancer: The Next Generation. Cell. 144(5): 646-674.

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Test your knowledge on the characteristics of benign and malignant tumors, the process of metastasis, and key concepts in cancer biology. This quiz covers significant aspects of carcinogenesis, tumor promoters, and risk factors associated with cancer. Ideal for students and enthusiasts of biology and medical studies.