Cancer: Cancer: Cell division gone wrongCell division gone wrong

Checkpoints in cell cycleCheckpoints in cell cycle Is the DNA fully

replicated? Is the DNA

damaged? Are there

enough nutrients to support cell growth?

Monitored by specialized proteins which send messages to nucleus to cell what to dohttp://youtu.be/VhkQP5g4EHo

A Basic DefinitionA Basic DefinitionCancer Cancer is defined as:is defined as: Disease caused by Disease caused by

uncontrolled growth and division of of defective cells.defective cells.

daughter cells continue daughter cells continue this destructive cell this destructive cell reproduction cyclereproduction cycle

Cell Growth Rates and CancerCell Growth Rates and Cancer Cancer Cancer occurs when:occurs when:

– Despite messages to STOP, a defective cell Despite messages to STOP, a defective cell continues to grow and divide continues to grow and divide

-a tumour is a lump of defective cells that develops-a tumour is a lump of defective cells that develops

The Two Types of TumoursThe Two Types of Tumours

1. Benign Tumours

2. Malignant Tumours

1. Benign Tumours1. Benign Tumours

Noncancerous lumpsNoncancerous lumps

Only harmful if the Only harmful if the lumps physically lumps physically crowd nearby tissuescrowd nearby tissues

2. Malignant Tumours2. Malignant Tumours CancerousCancerous Interfere with the regular functioning Interfere with the regular functioning

of surrounding cells and tissuesof surrounding cells and tissues May lead to May lead to metastasismetastasis

metastasismetastasis: occurs when : occurs when malignant tumour cells malignant tumour cells break off and form a break off and form a secondary tumour secondary tumour elsewhere in the bodyelsewhere in the body

eg. Renal (kidney) cancereg. Renal (kidney) cancer

Why is metastasis dangerous?Why is metastasis dangerous? Metastatic tumours may spread to vital areas Metastatic tumours may spread to vital areas

(blood, lungs etc..) and resulting in more severe (blood, lungs etc..) and resulting in more severe health problemshealth problems

Multiple locations of cancer are more difficult to Multiple locations of cancer are more difficult to treat.treat.

Cancer cannot Cancer cannot spread spread withoutwithout a a network of blood network of blood vessel to support vessel to support its growthits growth

Image from: http://www.cancer.gov/cancertopics/understandingcancer/angiogenesis/AllPages

What causes of Cancer?What causes of Cancer?

There are three general causes of cancerThere are three general causes of cancerMutations Caused by:Mutations Caused by:1.1. Random Error Mutation during DNA Random Error Mutation during DNA

replicationreplication2.2. CarcinogensCarcinogens3.3. Genes (Oncogenes)Genes (Oncogenes)

Random Error Mutations as a cause Random Error Mutations as a cause for Cancerfor Cancer

Errors in Errors in DNA duplication DNA duplication may occur during cell may occur during cell divisiondivision

UsuallyUsually, harmful mutations cause the cell to , harmful mutations cause the cell to self-destruct or refrain from dividing.self-destruct or refrain from dividing.

When does DNA duplication occur?S phase of cell cycle right before cell division

CarcinogensCarcinogens

Environmental factors that cause mutations Environmental factors that cause mutations in DNAin DNA

For example:For example:1. Tobacco smoke1. Tobacco smoke

CarcinogensCarcinogens EEnvironmental factors nvironmental factors

that cause mutations in that cause mutations in DNADNA

For example:For example:

2. Radiation2. RadiationSuch as UV rays (sun/tanning Such as UV rays (sun/tanning

beds)beds)

CarcinogensCarcinogens

EEnvironmental factors that cause mutations nvironmental factors that cause mutations in DNAin DNA

For example:For example:3. Chemicals like BPA3. Chemicals like BPA(bisphenol A)(bisphenol A)

CarcinogensCarcinogens

EEnvironmental factors that cause mutations nvironmental factors that cause mutations in DNAin DNA

For example:For example:4. Viruses 4. Viruses (HPV-(HPV-human papillomavirus can stay in the human papillomavirus can stay in the

body and lead to cervical cancerbody and lead to cervical cancer))

Cause of Cancer (Cont.): OncogenesCause of Cancer (Cont.): Oncogenes

Defective genes (due to mutations) are Defective genes (due to mutations) are passed down from one generation to passed down from one generation to another another

OncogenesOncogenes Family history can Family history can

indicate presence of indicate presence of oncogenesoncogenes

((OncologyOncology is is the study of the study of cancer)cancer)

• Examples of Examples of cancer that tend to cancer that tend to run in famillies: run in famillies: breast cancer & breast cancer & colon cancercolon cancer

Different Kinds of Cancer

Lung

Breast (women)

Colon

BladderProstate (men)

Some common sarcomas:Fat

Bone

Muscle

Lymphomas:Lymph nodes

Leukemias:Bloodstream

Some common carcinomas:

http://www.colorectal-cancer.ca/en/just-the-facts/symptoms/

Breast cancer

Colon cancer

Examples of cancer types

Which is the healthy lung? Which cancerous?

Healthy Cancerous

Smoking as a cause for CancerSmoking as a cause for Cancer 9 out of 10 cases of 9 out of 10 cases of

lung cancer in Canada lung cancer in Canada are a result of smokingare a result of smoking

Lung cancer is the most Lung cancer is the most common type of cancer common type of cancer in Canadians over 40in Canadians over 40

Can you explain why Can you explain why cigarettes are so cigarettes are so expensive and why expensive and why many Canadian many Canadian bars/clubs are smoke-bars/clubs are smoke-free?free?

Population-Based Studies

CANADA:Leukemia

Regions of Highest Incidence

BRAZIL:Cervicalcancer

U.S.:Coloncancer

AUSTRALIA:Skincancer

CHINA:Livercancer

U.K.:Lungcancer

JAPAN:Stomachcancer

Detecting CancerDetecting Cancer

Early detection of cancer is important to Early detection of cancer is important to prevent prevent metastasismetastasis

3 basic screening methods include:3 basic screening methods include:1.1. Genetic testing (for breast or colon cancer)Genetic testing (for breast or colon cancer)2.2. Self-exams (breast or prostate)Self-exams (breast or prostate)3. Medical diagnostics3. Medical diagnostics

Medical Diagnostic ToolsMedical Diagnostic Tools EndoscopyEndoscopy

– Fibre optic cable is inserted into Fibre optic cable is inserted into the body cavity to look for the body cavity to look for suspicious growthssuspicious growths

– Commonly used to Commonly used to detect colon detect colon cancerscancers

Observe a colonoscopyhttps://www.youtube.com/watch?v=ewCIqAAJGPg

Pill camera:https://www.youtube.com/watch?v=AlQN3c04mu0

Medical Medical DiagnosticsDiagnostics

X-RaysX-Rays– Images used to Images used to detect detect

cancer in bones and cancer in bones and lung tissuelung tissue

– MammogramMammogram is a is a specialized x-ray to specialized x-ray to examine examine breast tissuebreast tissue

Medical DiagnosticsMedical Diagnostics UltrasoundUltrasound

– Sound waves are Sound waves are used to examine used to examine soft tissuesoft tissue

– Detects Detects cancers cancers in heart or liver in heart or liver tissuetissue

Using ultrasound technology helps avoid the use of harmful X-rays (as in CAT scan)

Medical DiagnosticsMedical Diagnostics CT/CAT Scan CT/CAT Scan

(computerize(computerized axial d axial tomography)tomography)

– X-ray images X-ray images taken from taken from various angles various angles to access hard to access hard to see tissues to see tissues

– Often used to Often used to detect brain detect brain cancercancer

Medical DiagnosticsMedical Diagnostics MRI (magnetic MRI (magnetic

resonance resonance imaging)imaging)

– Radio waves and Radio waves and magnetic fields magnetic fields generate 3D generate 3D images with images with greater detail greater detail than CT scansthan CT scans

Medical DiagnosticsMedical Diagnostics Examining Cells and Examining Cells and

BiopsyBiopsy– Cells are taken via blood Cells are taken via blood

samples or surgery and samples or surgery and then examined under a then examined under a microscopemicroscope

– Based on irregular shape Based on irregular shape and smaller size, and smaller size, cancerous cells can be cancerous cells can be identifiedidentified

Conventional Cancer TreatmentsConventional Cancer Treatments

Cancer is generally treated in three ways:Cancer is generally treated in three ways:1.1. SurgerySurgery2.2. ChemotherapyChemotherapy3.3. RadiationRadiation

Surgery as Cancer TreatmentSurgery as Cancer Treatment Cancerous tissue is excised Cancerous tissue is excised

(cut) from the body(cut) from the body Benefits:Benefits: Ensures that most of the Ensures that most of the

cancerous cells are physically cancerous cells are physically removedremovedDisadvantage:Disadvantage:

Surgery can be risky, especially Surgery can be risky, especially in the elderly and infirmin the elderly and infirm

ChemotherapyChemotherapy

Drugs delivered to slow or stop cancer cell division. Drugs delivered to slow or stop cancer cell division. (May kill cancer cells sometimes)(May kill cancer cells sometimes)

Benefits:Benefits: Shrinks tumours for later surgical removal or radiation Shrinks tumours for later surgical removal or radiation

treatment- even small, hard-to- reach tumorstreatment- even small, hard-to- reach tumors Disadvantage:Disadvantage: Suffering from side effects (hair loss, nausea, fatigue)Suffering from side effects (hair loss, nausea, fatigue) May affect healthy cells but they can repair themselvesMay affect healthy cells but they can repair themselves

RadiationRadiation A focused beam of A focused beam of gammagamma radiation kills or radiation kills or

damages cancer cellsdamages cancer cells Benefits:Benefits: Can precisely target even Can precisely target even

small tumourssmall tumours Disadvantage:Disadvantage: May cause radiation sickness. May cause radiation sickness.

Also radiation exposure can Also radiation exposure can potentially cause other potentially cause other cancers.cancers.

https://www.youtube.com/watch?v=M1WdL61y_S8&feature=youtu.be

Recent advancementRecent advancement

The EndThe End