HE435 Lecture Notes - Lecture 18: Papillomaviridae, Ionizing Radiation, Cervical Cancer
HE435 Week 7 Lecture 18
Cancer – 1
Cancer Overview
• Primary cause (along with CVD) of premature death
• Uncontrolled cell growth resulting in compression, invasion, and degradation of
surrounding tissue
• Malignant cells also transported through the blood & lymphatic system to peripheral
organs resulting in secondary colonies (metastases)
• Underlying mechanism is changes in genetic material (mutation)
o Caused by environmental factors (i.e. radiation, pollution, tobacco)
o The mutations cause cell properties to change and mechanisms controlling
lifespan to be disturbed (cancer cells live unhindered and uncontrolled)
What Causes Cancer?
• Causes of cancer: varied and still not clearly understood
• Cancer involves:
o Hyperplasia (growth of too many cells)
o Anaplasia (development of undifferentiated cells)
• Cancer arises from the mutation of a normal gene
• Mutated genes that cause cancer are called oncogenes
• Several mutations likely needed to give rise to cancer
• Cells that are old or not functioning properly normally self destruct and are replaced by
new cells
o However, cancerous cells do not self destruct and continue to divide rapidly
producing millions of new cancerous cells
• A factor which brings about a mutation is called a mutagen
• A mutagen is mutagenic
• Any agent that causes cancer is called a carcinogen and is described as carcinogenic
• Therefore, some mutagens are carcinogenic
Carcinogens
• Ionising radiation – x-rays, UV light
• Chemicals – tar from cigarettes
• Virus infection – papilloma virus can be responsible for cervical cancer
• Hereditary predisposition
o Some families are more susceptible to getting certain cancers
o You can’t inherit cancer, its just that you maybe more susceptible to getting it
