Cancer: Cell division gone wrong

A Basic Definition Cancer is : Disease caused by uncontrolled growth and division of defective cells. Disease caused by uncontrolled growth and division of defective cells. daughter cells continue in this destructive cell reproduction cycle daughter cells continue in this destructive cell reproduction cycle

Cell Growth Rates and Cancer Cancer occurs when: Cancer occurs when: –Despite messages to STOP, a defective cell continues to grow and divide -a tumour (lump of defective cells) develops

The Two Types of Tumours Benign Tumours Malignant Tumours

Benign Tumours Noncancerous lumps Noncancerous lumps

Benign Tumours Noncancerous lumps Noncancerous lumps Only harmful if the lumps physically crowd nearby tissues Only harmful if the lumps physically crowd nearby tissues

Malignant Tumours Cancerous Cancerous

Malignant Tumours Cancerous Cancerous Interfere with the regular functioning of surrounding cells and tissues Interfere with the regular functioning of surrounding cells and tissues

Malignant Tumours Cancerous Cancerous Interfere with the regular functioning of surrounding cells and tissues Interfere with the regular functioning of surrounding cells and tissues May lead to metastasis May lead to metastasis

Metastasis malignant tumour cells may break off and form a secondary tumour elsewhere in the body malignant tumour cells may break off and form a secondary tumour elsewhere in the body eg. Renal (kidney) cancer

Metastasis Dangerous because: Metastatic tumours may spread to vital areas (blood, lungs etc..) and resulting in more severe health problems Metastatic tumours may spread to vital areas (blood, lungs etc..) and resulting in more severe health problems Multiple locations of cancer are more difficult to treat. Multiple locations of cancer are more difficult to treat.

Causes of Cancer There are three general causes of cancer Mutations Caused by: 1. Random Error Mutation during DNA replication 2. Carcinogens 3. Genes (Oncogenes)

Random Error Mutations as a cause for Cancer Errors in DNA replication may occur during cell division Errors in DNA replication may occur during cell division Usually, harmful mutations cause the cell to self-destruct or refrain from dividing. Usually, harmful mutations cause the cell to self-destruct or refrain from dividing.

Carcinogens Environmental factors that cause mutations Environmental factors that cause mutations For example: For example: –Tobacco smoke

Carcinogens Environmental factors that cause mutations Environmental factors that cause mutations For example: For example: –Radiation

Carcinogens Environmental factors that cause mutations Environmental factors that cause mutations For example: For example: –UV rays (sun/tanning beds)

Carcinogens Environmental factors that cause mutations Environmental factors that cause mutations For example: For example: –Chemicals like BPA (bisphenol A)

Carcinogens Environmental factors that cause mutations Environmental factors that cause mutations For example: For example: –Viruses (HPV- human papillomavirus can stay in the body and lead to cervical cancer )

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

Oncogenes Family history can indicate presence of oncogenes Family history can indicate presence of oncogenes

Oncogenes Defective genes (mutations) are passed down from one generation to another Defective genes (mutations) are passed down from one generation to another Family history can indicate presence of oncogenes Family history can indicate presence of oncogenes (Oncology is the study of cancer) (Oncology is the study of cancer) Examples: Examples: breast cancer & colon cancer

Smoking as a cause for Cancer 9 out of 10 cases of lung cancer in Canada are a result of smoking 9 out of 10 cases of lung cancer in Canada are a result of smoking Lung cancer is the most common type of cancer in Canadians over 40 Lung cancer is the most common type of cancer in Canadians over 40 Can you explain why cigarettes are so expensive and why many Canadian bars/clubs are smoke-free? Can you explain why cigarettes are so expensive and why many Canadian bars/clubs are smoke-free?

Smoking as a cause for Cancer

Detecting Cancer Cancer can be detected even before the patient shows symptoms Cancer can be detected even before the patient shows symptoms Important to catch cancer early to prevent metastasis Important to catch cancer early to prevent metastasis Screening methods include: Screening methods include: –Genetic testing (for breast or colon cancer) –Self-exams (breast or prostate) –Medical diagnostics

Medical Diagnostics Endoscopy Endoscopy –Fibre optic cable is inserted into the body cavity to look for suspicious growths –Commonly used to detect colon cancers

Medical Diagnostics X-Rays X-Rays –Images used to detect cancer in bones and lung tissue –Mammogram is a specialized x-ray to examine breast tissue

Medical Diagnostics Ultrasound Ultrasound –Sound waves are used to examine soft tissue –Detects cancers in heart or liver tissue

Medical Diagnostics CT/CAT Scan (computerized axial tomography) CT/CAT Scan (computerized axial tomography) –X-ray images taken from various angles to access hard to see tissues –Often used to detect brain cancer

Medical Diagnostics MRI (magnetic resonance imaging) MRI (magnetic resonance imaging) –Radio waves and magnetic fields generate 3D images with greater detail than CT scans

Medical Diagnostics Examining Cells and Biopsy Examining Cells and Biopsy –Cells are taken via blood samples or surgery and then examined under a microscope –Based on irregular shape and smaller size, cancerous cells can be identified

Conventional Cancer Treatments Cancer is generally treated in three ways: Cancer is generally treated in three ways: 1. Surgery 2. Chemotherapy 3. Radiation

Surgery as Cancer Treatment Cancerous tissue are excised (cut) from the body Cancerous tissue are excised (cut) from the body Ensures that most of the cancerous cells are physically removed Ensures that most of the cancerous cells are physically removed Surgery can be risky, especially in the elderly and infirm Surgery can be risky, especially in the elderly and infirm

Chemotherapy Drugs delivered to slow or stop cancer cell division. (May kill cancer cells sometimes) Drugs delivered to slow or stop cancer cell division. (May kill cancer cells sometimes) Shrinks tumours for later surgical removal or radiation treatment- even small, hard- to- reach tumors Shrinks tumours for later surgical removal or radiation treatment- even small, hard- to- reach tumors Suffering from Side effects (hair loss, nausea, fatigue) Suffering from Side effects (hair loss, nausea, fatigue)

Radiation A focused beam of A focused beam of gamma radiation kills or damages cancer cells gamma radiation kills or damages cancer cells Can precisely target even small tumours Can precisely target even small tumours May Cause radiation sickness. Radiation exposure might cause other cancers. May Cause radiation sickness. Radiation exposure might cause other cancers.

The End