7. Biology of Cancer

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Questions and Answers

What are the primary factors that regulate organ and body size?

Cell growth, division, and survival (correct)

Cell signaling and immune response

Cell metabolism and apoptosis

Cell growth and differentiation

Which checkpoint in the cell cycle is primarily controlled by Cdk and Cyclins?

G1/S checkpoint (correct)

G0 phase checkpoint

M phase checkpoint

G2/M checkpoint

What role do mitogens play in the cell cycle?

Inhibit cell division

Promote cell death

Suppress cell growth

Stimulate cell division (correct)

Which of the following factors promote cell survival?

Survival factors Signup and view all the answers

Which phase of the cell cycle is characterized by a cell being inactive and not preparing to divide?

G0 phase Signup and view all the answers

Which type of factors trigger a G1/S-Cdk activity wave?

Growth factors Signup and view all the answers

What type of genetic mutations are primarily associated with tumour suppressor genes?

Recessive mutations that require multiple events Signup and view all the answers

What is the main function of cyclins in the cell cycle?

Regulate checkpoint timings Signup and view all the answers

What is the primary function of the Retinoblastoma Protein (pRb)?

Initiating the cell-division cycle Signup and view all the answers

Which of the following correctly describes the role of the Ras protein within cell signaling?

Is a GTPase that regulates cell growth pathways Signup and view all the answers

What is the consequence of a loss of function mutation in the RB gene?

Unregulated entry into S-phase Signup and view all the answers

In the context of cancer signaling, what is the role of the RTK/Ras/PI3K pathway?

Regulates epithelial tissue development and homeostasis Signup and view all the answers

What is a characteristic feature of malignant tumors?

They can spread to other parts of the body. Signup and view all the answers

Which type of carcinoma resembles stratified squamous epithelium?

Squamous cell carcinoma Signup and view all the answers

What does the term 'metastasis' refer to in cancer biology?

The spread of cancer cells to different body parts. Signup and view all the answers

Which of the following is NOT a type of malignant tumor?

Adenoma Signup and view all the answers

What is the main role of the cell-cycle control system during mitosis?

To ensure accurate chromosomal DNA segregation Signup and view all the answers

What is the primary challenge associated with cancers originating in the brain?

Surgical removal can be complicated due to their vulnerable position. Signup and view all the answers

Which phase immediately follows the G1 phase in the cell cycle?

S phase Signup and view all the answers

Which of these is a characteristic that distinguishes benign tumors from malignant tumors?

Malignant tumors often recur after removal. Signup and view all the answers

At what checkpoint is the commitment to DNA replication made?

End of G1 Signup and view all the answers

In what way can cancer cells increase their growth signal response?

By altering metabolic pathways Signup and view all the answers

What happens during the G2/M transition of the cell cycle?

Chromosome alignment on the mitotic spindle occurs Signup and view all the answers

Which type of cancer affects white blood cells?

Leukemia Signup and view all the answers

Which process involves cyclin-Cdk complex activity?

Phosphorylation of substrates Signup and view all the answers

What is a common feature encountered in most cancer types?

Increased tissue invasion Signup and view all the answers

What is true about the G0 phase of the cell cycle?

Most cells in the body are in a nondividing state Signup and view all the answers

What is one method through which cyclin-dependent kinases (Cdks) can be inactivated?

Ubiquitination Signup and view all the answers

Which event occurs during the metaphase-to-anaphase transition?

Sister-chromatid separation Signup and view all the answers

Which of the following is NOT a phase in the cell cycle?

C phase Signup and view all the answers

What is the primary purpose of proto-oncogenes?

To help cells grow, divide, and stay alive Signup and view all the answers

Which stage of cancer indicates that it has spread to at least one other body organ?

Stage 4 Signup and view all the answers

Which of the following factors is NOT a contributor to cancer development?

Exercise Signup and view all the answers

What does the T in the TNM staging system represent?

Tumor size Signup and view all the answers

What is the significance of oncogenes in cancer biology?

They are mutated proto-oncogenes that can cause cancer Signup and view all the answers

Which type of infections significantly contribute to specific cancers?

Bacterial and viral infections Signup and view all the answers

What is a common result of failed DNA repair in cancer development?

Accumulation of DNA damage Signup and view all the answers

Which stage in the cancer progression involves larger tumor size but no spread?

Stage 2 Signup and view all the answers

How much of cancers could potentially be prevented by lifestyle changes?

Up to 50% Signup and view all the answers

Which component is NOT part of the TNM staging system?

R for Recurrence Signup and view all the answers

Study Notes

Molecular Medicine - Introduction to the Molecular Biology of Cancer

The course is titled XY3121: Molecular Medicine.
The module's focus is on the molecular biology of cancer.
The lecturer is Dr Peter Oatley, with the email address [email protected].
The institution offering the course is the University of Central Lancashire (UCLan).

Learning Outcomes - Part 1: Cell Cycle Checkpoints

Students need to recall the phases of the cell cycle.
Students need to grasp the function of cyclins and cyclin-dependent kinases (CDKs) within the cell cycle.
Students must know the function of the three primary checkpoints in the cell cycle and their regulation.

Lecture Structure - Part 1: Cell Cycle Checkpoints

Organ/body size regulation is a key aspect
The cell cycle will be reviewed
The three checkpoints described
Cyclins and their regulation
This aspect focuses on the checkpoints 1–3 of the cell cycle

The Cell Cycle - Organ/body size regulation

Balance of cell growth, cell division, and cell survival is crucial.
Regulation is governed by cell signaling.
External factors influence cell signaling and regulation
- Mitogens stimulate cell division
- Growth factors encourage cell growth.
- Survival factors promote cell survival and counter apoptosis.

The Cell Cycle - Recap

Mitosis is the process of cell division.
Accurate chromosomal segregation is vital for mitosis.
The cell cycle control system regulates mitosis.
Phases of the cell cycle: G1, S, G2, and M (mitosis).

The Cell Cycle - Checkpoints

End of G1 (G1/S Transition):
- Deciding on entering the cell cycle and replication.
G2/M transition:
- Early mitotic events are critical for chromosome alignment on the mitotic spindle.
Metaphase-to-anaphase transition:
- Sister chromatid separation is essential

Checkpoints regulated by Cyclin-Cdk complex activity

Checkpoints are controlled by the cyclin-CDK complex.
Various factors, such as extracellular environment changes and DNA damage, influence checkpoints.

The Cell Cycle - Cyclins

Cyclins induce CDK autophosphorylation and CDK activation.
Active cyclin-CDK complexes phosphorylate substrates.
The function of Cks1 in CDK1 interactions.

Cell Cycle Checkpoints - Cyclin Regulation

Inhibitors, phosphorylation, and ubiquitin play a role in cyclin regulation.

The Cell Cycle - G0

Most cells in the body are quiescent (in G0).
The cell cycle control system is disassembled.
Cyclin-dependent kinase (CDK) gene expression is permanently turned off in cells such as neurons.
Mitogens can reactivate these cells to enter the G1 phase.

Checkpoint 1 - G1 → S

G1/S-cyclin accumulates, driving the G1-to-S transition.
Active G1/S and S cyclins trigger DNA synthesis in the S phase.

Checkpoint 2 - G2/M

S cyclins steadily rise and then plateau.
M cyclins increase during G2 and peak at the very end of the G2 phase.
M-CDK is prepared for later activation.

Checkpoint 3 - Metaphase-to-anaphase

Metaphase-to-anaphase transition is governed by the APC/C complex as an ubiquitin ligase family member.

Cancer Introduction

Cancers originate in the various tissues of the body(eg brain, lung, breast, stomach).
A significant percentage of cancers are preventable through lifestyle changes.
A wide variety of risk factors contribute to cancer development
The initial transformation from normal cells to cancer cells and the development of tumours results from a variety of factors working together.
Many features distinguish benign and malignant tumors from one another
The process of metastasis is crucial in cancer progression

Cancer Critical Genes - Definitions

Proto-oncogenes are normal genes involved in cell growth, division, and survival.
Oncogenes are mutated proto-oncogenes that promote uncontrolled cell proliferation.
Tumour suppressor genes regulate cell division, DNA repair, and apoptosis to prevent tumour development.

Cancer Critical Genes - Retinoblastoma (RB)

Retinoblastoma is a childhood tumour arising in the retina.
The RB gene regulates cell-cycle progression.
Loss-of-function mutations can result in unregulated cell entry into the S-phase of cell cycle progression.

Cancer Critical Genes - RAB (Ras protein)

Ras protein is part of the RTK/Ras/PI3K pathway, involved in cell signal transduction.
Mutations within the Ras pathway contribute to uncontrolled cell proliferation and are a target for anticancer drugs.
Active Akt inhibits apoptosis, allowing for cancer cell survival.
The PI3K/Akt/mTOR pathway plays a role in cell regulation.

Cancer Critical Genes - TP53

The p53 protein is involved in cell cycle control, DNA repair, and apoptosis.
Mutations in the p53 gene are frequent in many cancers, leading to disrupted cell function.
The p53 pathway is a major focus of ongoing cancer research
Drug therapies target and restore normal function in the p53 pathways

Cancer Diagnosis

Various methods, like blood tests, imaging (MRI/CT), and biopsy, are used for diagnosis.
Cancer grades are classified based on the appearance of cells under a microscope.
Different characteristics in tumour cells differentiate between benign and malignant tissues.

Studying That Suits You

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Description

This quiz explores the fundamental concepts of cell cycle checkpoints in the context of cancer biology. Students will be tested on their understanding of the phases of the cell cycle, the role of cyclins and cyclin-dependent kinases, and the regulation of the three main checkpoints. Prepare to delve into the molecular mechanisms that control cell division and organ size.