Lecture 30: Cancer Chemotherapy Flashcards
What is cancer?
cancer is the leading cause of death in Canada (1 in 4 deaths)
over 100 types of cancers
characterized by abnormal cell growth with potential to spread to other parts of the body (metastasis)
What are the causes of cancer?
caused by environmental and genetic factors
tobacco, ionizing radiation, environmental pollution (asbestos, radon)
viral infections (HIV with Hodgkins and non-Hodgkins Lymphoma; Human Papiloma Virus with cervical cancer)
genetics (BRCA 1 in breast cancer)
What is the relationship between cancer and the cell cycle?
cancer is fundamentally a disease of cell growth regulation
cancer arises when genes that regulate cell growth are mutated
What is the cell cycle?
the cycle is a series of events leading to duplication of DNA and division of cytoplasm to produce two daughter cells
genes important in the regulation of cell cycle are divided into two daughter cells
What is the G1 phase of the cell cycle?
checkpoint to ensure cell ready for DNA synthesis
What is the S phase of the cell cycle?
DNA synthesis
What is the G2 phase of the cell cycle?
checkpoint to ensure cell ready for mitosis
What is the M phase of the cell cycle?
mitotic phase (cell divides into two daughter cells)
What is the G0 phase of the cell cycle?
quiescent state
What are tumor suppressor genes?
tumor suppressor genes (and the proteins they encode) repress cell cycle or promote apoptosis
inhibit cell division
initiate apoptosis following irreversible DNA damage
DNA repair proteins (BRCA)
p53 is a tumor suppressor protein that regulates cell cycle
p53 is mutated in 50% of all tumor
What are proto-oncogenes?
are normal genes involved in cell growth and proliferation or inhibition of apoptosis
mutations can increase expression and proliferation (oncogene)
What are point mutations?
small scale deletions or insertions which affect its expression
What is chromosomal translocation?
when two separate chromosomal regions become abnormally fused
What is the Philadelphia chromosome?
is a specific genetic abnormality in chromosome 22 found in leukemia cancer cells (abnormal translocation of chromosome 9 and 22)
the broken end of chromosome 22 contains the BCR gene which fuses with a fragment of chromosome 9 that contains the ABL1 gene
fusion creates a new gene BCR-ABL
leads to unregulated expression of protein tyrosine kinase activity (ABL gene) leading to unregulated cell cycle and cell division
What is relationship between oncogenes and cancer?
usually multiple oncogenes and mutated tumor suppressor genes will all act in concert to cause cancer