Cancer Flashcards
General overview of cancer
Genes inside each cell tell it when to grow, work, divide and die. Normally, our cells follow these instructions and we stay healthy. But sometimes the instructions get mixed up, causing our cells to grow and divide out of control or not die when they should.
As more and more of these abnormal cells grow and divide, they can form a lump in the body called a tumor
Hyperplasia
means that abnormal cells are dividing and increasing in number faster than normal. The cells look normal under the microscope but there are more cells than normal. Some types of hyperplasia are precancerous but most aren’t
i.e. BPH
Atypia
means that cells are slightly abnormal (atypical).
Sometimes atypia may be caused by healing and inflammation but some types of atypia are precancerous.
Metaplasia
means that there has been a change to the types of cells that are normally found in this area of the body. The cells look normal but they aren’t the type of cells that are normally found in that tissue or area. Most types of metaplasia aren’t precancerous but some are.
Dysplasia
means that cells are abnormal, there are more cells than normal, the cells are growing faster than normal and they aren’t arranged like normal cells. Dysplasia is a precancerous condition.
Carcinoma in situ
is the most severe type of precancerous change. The cells are very abnormal but have not grown into nearby tissue. Carcinoma in situ is usually treated because it has a high risk of developing into cancer.
Precancerous changes can be mild to severe. There are different ways of describing precancerous changes based on how mild or severe the changes are.
Hyperplasia
Atypia
Metaplasia
Dysplasia
Carcinoma in situ
People with precancerous conditions are usually checked regularly, so they can be treated quickly if cell changes become more severe or turn into cancer.
Describe normal cellular differetiation
Orderly process progressing from a state of immaturity to a state of maturity
Stable and will not change
Exact mechanism of normal cellular differentiation not completely understood
Most human tissues contain _____-stem cells.
predetermined, undifferentiated
All cells are controlled by a_______________ that determines proliferation.
intracellular mechanism
Cancer cells grown in culture are characterized by loss of
contact inhibition.
Stem cell theory of defect in cellular proliferation
Loss of intracellular control of proliferation results from mutation of stem cells.
DNA is substituted or permanently rearranged.
Two types of genes that can be affected by mutation are
Proto-oncogenes
Regulate normal cellular processes such as promoting growth
Tumour suppressor genes
Suppress growth
Proto-oncogenes
Genetic locks that keep cells functioning normally
Mutations that alter their expression can activate them to function as oncogenes (tumour inducing genes).
Which can interfere with normal cell growth causing the cell to become malignant.
Like a gas pedal, helping cell grow and dvide
oncogenes are like gas pedals that are stuck down - out of control
Tumour suppressor genes
Function to regulate cell growth
Suppress growth of tumours
Are rendered inactive by mutations
Result in loss of suppression of tumour growth
BRCA1 and BRCA2 genes
if mutated, increase risk of ovarian cancer and breast cancer
What happens to cells once they mutate
Cells can die from damage or by initiating programmed cellular suicide (apoptosis).
Can recognize damage and repair itself
Can survive and pass on damage to two or more daughter cells
Surviving mutated cells have potential to become malignant.
When do normal cells divide
When new cells are required
Malignant or cancer cells and adhereance
Less adherant and more mobile than normal cells
Normal cells adhere to
Other normal cells
Angiogenesis
Cancer cells have the ability to secrete a substance that stimulates blood vessel growth to support the rapidly growing mass. This is called angiogenisis
Do normal cells or cancer cells die more easily
Cancer cells do not die as easy
Development of cancer, origin of cancer may be
Radiation
Viral/bacterial
lifestyle
environemnt
How do cells go from normal to neoplastic
Mutation of cell’s genetic structure
From inherited mutation
From exposure to a chemical, radiation, or viral agent
Many carcinogens are detoxified and harmlessly excreted. If not they enter the cells nucleus and alter its DNA.
Mutated cell has the potential to develop into neoplastic cells.