Cancer is not a single disease; it is a myriad or collection of diseases with many different manifestations as there are many different types of tissues and cell types
Cancer is a disease of abnormal gene expression.
Cells are constantly evolving and have the natural selection pressures to change
Common biological properties of tumor cells:
1) Deregulated clonal cell growth- all cells in a tumor originated from one single cell that acquired mutations that made it deregulated cancer cells are constantly testing different mutations so they are constantly changing
2) Impaired cellular differentiation - cancer cells have lost the ability to differentiate. Cells stop growing once they differentiate so cancer cells can't differentiate therefore they keep growing
3) Invasiveness -benign tumor are localized and encapsulated, malignant tumors invade surrounding areas
4) Metastatic potential- not only have they become invasive but they have spread to secondary or distal sites
Cancer cells become deprogrammed
Proto-oncogenes encode for positive mediators of cell proliferation and growth. They drive the proliferation of the cell ex: growth factor receptor
Tumor suppressor gene encode negative growth regulatory factors. They counter the effects of protooncogenes. In cancer cells they bypass the negative effects of these so they continue to grow
Cancer epidemiology is the study of distribution of various cancer types among world populations with consideration of specific risk factors and etiologic agents involved in disease causation such as age, ethnicity or even exposure to carcinogens
Cancer epidemiology is the study of cancer instance, mortality, risk factors, and attempting to relate and find causation
A carcinogen does not necessarily cause cancer but it can cause a progression of the disease such as a benign tumor becoming malignant
Any abnormal growth is cancer there is just a difference between