Example of benign neoplasm with a rapid growth rate
leimyoma in the uterus
Approximate growth characteristic?
1 tumor of 10 microm will generate a 1mg tumor in about 30 cell cycles
How many cycles are required to produce a 1kg tumor?
40 cycles
Detectable tumor size
1mg
What are the 2 theories for tumor growth?
- Monoclonal theory of neoplasms
- Cancer stem cell hypothesis
What is the monoclonal theory of neoplasms?
1 cell has a genetic “hit” and becomes neoplastic, and all other cells are daughter cells of this one cell
What is the cancer stem cell hypothesis?
That neoplastic cells have stem cell characteristics and form 2 daughter cells : one with self renewal and one with differenciation
Phases of growth
- proliferative phase
- non-proliferative phase
Which phase is targetted by chemotherapeutic agents?
The proliferative phase - doesn’t target G0
How to determine tumor growth?
= doubling time (proliferation rate) + rate of dying
What does rate of growth depend on? (6)
- rate of cell production
- growth fraction
- rate of shedding of cells
- differenciation
- blood supply
- pressure
Examples of high proliferative cancers (3)
- Acute leukemias
- High grade lymphomas
- SCLC
Examples of low proliferative cancers (2)
- colon cancer
- breast cancer
