Cancer Biology Fundamentals

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Questions and Answers

Which of the following best describes the role of oncogenes in cancer development?

They code for proteins that are part of the cell's growth inhibitory feedback loop.

They are the result of loss of function mutations in genes controlling cell survival.

They act as negative regulators, suppressing cell proliferation and survival.

They are positive regulators of proliferation or survival, exhibiting dominant activity. (correct)

What is a key difference between the actions of oncogenes and tumor suppressor genes?

Oncogenes act in a dominant fashion, whereas tumor suppressor genes typically act in a recessive fashion. (correct)

Oncogenes control programmed cell death, while tumor suppressor genes control uncontrolled cellular proliferation.

Oncogenes require mutations in both alleles to cause change, while tumor suppressor genes only require mutation in a single allele.

Oncogenes typically result from loss-of-function mutations while tumor suppressor genes result from gain-of-function.

Which of the following is NOT considered a hallmark of cancer?

Enhanced cellular differentiation (correct)

Inducing angiogenesis

Evading growth suppressors

Sustaining proliferative signaling

What role does genomic instability play in the development of cancer?

It generates genetic diversity that facilitates the acquisition of cancer hallmarks. Signup and view all the answers

Which cellular process is NOT explicitly mentioned as a common factor contributing to cancer development?

Normal tissue repair Signup and view all the answers

What do proto-oncogenes become after acquiring mutations?

Oncogenes Signup and view all the answers

Which of the following is NOT a mechanism by which tumors develop?

Through cells with normal apoptosis Signup and view all the answers

Which of the following is considered an emerging hallmark of cancer development?

Reprogramming of energy metabolism Signup and view all the answers

What is a primary reason why extravasated cancer cells might fail to form a metastasis?

They enter a dormant state or are arrested in the cell cycle. Signup and view all the answers

Which of the following best describes the impact of immunosuppression on metastasis?

It may create an environment that allows metastasis to spread more easily. Signup and view all the answers

How can inflammation contribute to the spread of cancer?

By producing tumor-supporting factors from neutrophils. Signup and view all the answers

Which of the following refutes the reductionist view of tumors?

Tumors are not merely made up of cancer cells but also a variety of recruited normal cells. Signup and view all the answers

What is the meaning of 'tumor microenvironment' in cancer biology?

The repertoire of recruited, ostensibly normal cells that contribute to the tumor. Signup and view all the answers

The complexity of a tumor is now understood to be comparable to:

Normal, healthy organs. Signup and view all the answers

What is one fundamental shift in the understanding of tumor biology?

Moving from considering a tumor as a collection of homogenous cells to seeing them as more complex with specialized cell types. Signup and view all the answers

Studying tumors from the contemporary new perspective requires an investigation of

The individual specialized cell types and the 'tumor microenvironment'. Signup and view all the answers

What is a key characteristic of the stromal components associated with a growing tumor, as described in the text?

They are of non-neoplastic origin and do not carry mutations. Signup and view all the answers

How has the understanding of the tumor microenvironment influenced cancer therapy?

It has shifted the focus towards therapies that modify the tumor's surrounding environment. Signup and view all the answers

What role does the microenvironment play in the production of growth factors?

It can be manipulated by the tumor cells to produce growth factors. Signup and view all the answers

Why is the tumor microenvironment considered a potential therapeutic target?

Due to tumors not always being entirely independent in their growth, which makes the microenvironment a potential therapeutic target. Signup and view all the answers

What is a key aspect of cancer therapy as described in the text, with respect to growth factors?

Tumor cells often have mutations that enhance their response to growth factors produced by surrounding cells. Signup and view all the answers

Which of the following best describes cancer according to the text?

The outcome of a multistep process, and not a single disease with variable pathogenesis. Signup and view all the answers

What is the relationship between a primary culture and a cell line?

A cell line is the first subculture obtained from a primary culture. Signup and view all the answers

According to the provided content, what knowledge areas should a modern oncologist possess?

Molecular biology, experimental models, clinical trials, precision medicine and also history. Signup and view all the answers

What is a primary limitation of the initial empirical approach for drug discovery?

It selects for drugs active only on fast-growing, highly proliferative cells. Signup and view all the answers

What characteristic of cancer cells is suggested when they grow on plastic in a basic medium?

They are more aggressive than the original tumor cells and can survive in less rich conditions. Signup and view all the answers

What is a 'continuous cell line'?

A cell line that can grow indefinitely due to a genetic transformation and serial passaging. Signup and view all the answers

What kind of bias is inherent in the results of the initial empirical drug-screening method?

A bias in favor of compounds active on actively proliferating cells. Signup and view all the answers

Why are solid tumors more challenging to treat based on traditional preclinical models?

Because they generally have a lower percentage of cells actively dividing. Signup and view all the answers

What is the purpose of pre-screening drugs on human cell lines and using mice models?

To assess drug efficacy and toxicity before human trials. Signup and view all the answers

What is a major limitation of drugs discovered using cell culture that only stop cell proliferation?

They may fail to target dormant cells that do not proliferate. Signup and view all the answers

What is a key difference between primary cell cultures and continuous cell lines?

Primary cultures have a finite lifespan, but continuous cell lines can grow indefinitely upon genetic transformation. Signup and view all the answers

What is the primary characteristic of most current cancer drugs?

Anti-proliferative action Signup and view all the answers

Which of the following is a common side effect of many current cancer drugs?

Hair loss Signup and view all the answers

What is meant by an 'empirical approach' in the context of drug development?

Development where the drug's mechanism and cellular target are initially unknown Signup and view all the answers

What is the main focus that defines 'Precision Medicine'?

Finding the right treatment for the right patient at the right time Signup and view all the answers

What is one benefit of precision medicine for patients?

Avoidance of under-treatment Signup and view all the answers

Why is it important to continuously monitor a tumor's evolution?

Because the tumor's genetic signature at diagnosis may not be the same after treatment Signup and view all the answers

What does 'multi-omics' refer to in cancer research?

The combined study of genetic, proteomic and other biological data Signup and view all the answers

What information can be derived from studying RNA in multi-omics analysis?

Which genes are being expressed Signup and view all the answers

What is the primary consequence of a malfunction in DNA repair systems?

An accumulation of mutations in key genes. Signup and view all the answers

What is the defining characteristic of a driver mutation?

It confers a selective advantage to the cell. Signup and view all the answers

What best describes the relationship between hallmarks of cancer?

A complex network of interrelations that vary between and within cells. Signup and view all the answers

Why is tumor heterogeneity considered favorable for tumor development?

It allows the tumor to adapt and survive in diverse conditions. Signup and view all the answers

What was the historical view of metastasis within the cancer development process?

The final stage of tumor evolution, arising only in advanced tumors. Signup and view all the answers

What does the parallel progression model of metastasis propose?

Metastatic cells evolve alongside the primary tumor from the beginning. Signup and view all the answers

What is a key characteristic of the invasion-metastasis cascade?

It requires the ability to adapt to several diverse environments. Signup and view all the answers

Why could the parallel progression model of metastasis require a more aggressive treatment approach?

Because it suggests that metastatic potential can already be present from the tumor's inception. Signup and view all the answers

Study Notes

Tumor Biology for Clinicians

Cancer develops in cells that are highly proliferative (e.g., lymphocytes, intestines), frequently exposed to environmental carcinogens (e.g., lungs, intestines), and whose proliferative activity is under hormonal control (e.g., breast, prostate).

Hallmarks of Cancer

The hallmarks of cancer are six biological capabilities acquired during the development of human tumors.
These hallmarks include:
- Sustaining proliferative signaling
- Evading growth suppressors
- Resisting cell death
- Enabling replicative immortality
- Inducing angiogenesis
- Activating invasion and metastasis
Genome instability and inflammation expedite the acquisition of these hallmarks.
Additional emerging hallmarks include reprogramming of energy metabolism and evading immune destruction.

Cancer Associated Genes

Oncogenes are positive regulators of proliferation or survival. Mutations in them lead to increased activity (gain of function).
- Examples include EGFR, Ras, and Myc.
Tumor suppressor genes are negative regulators of proliferation or survival. Mutations in them lead to decreased activity (loss of function).
- Examples include Rb, p53, and CKI.

Clonal Evolution in Cancer

Cancer development is a multi-step process requiring the accumulation of mutations.
The DNA repair system is crucial, dysfunction in this system enables the accumulation of mutations in key genes.
Driver mutations: Mutations contributing to cancer by giving cells an advantage.
Passenger mutations: Neutral mutations without any benefit to the cell.

Oncogenic Events

Tumor development isn't linear; it's complex and involves interactions between cells.
Tumors are heterogeneous; cells evolve independently within the tumor.
This heterogeneity allows tumors to adapt and survive in the body.

Metastasis

Linear Progression: Historically, metastasis was seen as a late-stage event. However, this is not always true.
Parallel Progression: Some types of cancer have metastatic cells developing alongside the primary tumor from the start.
Understanding the timing of metastasis is critical in treatment planning.

Invasion-Metastasis Cascade

This process describes the stepwise progression of tumor cells from the original site to distant locations.
The steps include local invasion, intravasation, transport, arrest, extravasation, survival and re-initiation.

The Role of the Microenvironment

Tumors contain a complex network of cells and factors beyond just the cancer cells themselves.
The microenvironment significantly impacts tumor development, survival and treatment response.
The microenvironment can influence the production of growth factors.
Factors like inflammation and immune responses play vital roles in tumor progression

Precision Medicine

Precision medicine focuses on targeting specific genetic mutations within a tumor for effective and targeted therapy.
It recognizes that cancer heterogeneity requires individualized treatment strategies.
The goal is to tailor therapies to specific tumor characteristics (mutations) to avoid side effects.

History of Cancer Research

Earlier research focused on screening drugs broadly effective against rapidly dividing cells.
Later, modifying these screening procedures, researchers identified more specific drugs.
The development of newer methodologies was crucial for effectively identifying effective therapies for many cancers.
Research has evolved from broad screening methods to a precise approach focused on specific mutations.

More "Omics"

This points to advancements involving the study of multiple levels within a cell/organism, including genomics, epigenomics, transcriptomics, protonomics, and metabolomics.
These methods provide increasingly comprehensive profiles of the tumor characteristics, which is important when developing effective therapies.

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Description

Test your knowledge on oncogenes, tumor suppressor genes, and the various factors contributing to cancer development. This quiz covers key concepts, emerging hallmarks, and the tumor microenvironment. Understand the complexities of cancer biology and its implications.