Barsky: Cancer Flashcards
Men have the highest incidence of which cancer?
Women have the highest incidence of which cancer?
Both men and women have the highest death rates from which cancer?
prostate; breast; lung
Two factors leading to tumor progression?
genetic: mutations, rearrangements in proto-oncogenes
epigenetics
It’s important to know that cancer is a multi-hit event. Why does this help explain why cancer is a disease of aging?
It takes years to accumulate “hits” - this is why neonates don’t get cancer
Why is it important to catch cancer when it is “in situ” vs. invasive?
To become metastatic/invasive, cancer must break through the epithelial barriers of the blood or lymph vessels and spread through the circulation. If it is still contained within its barriers, the cancer cells can be surgically removed and rid of before it spreads systemically.
**once you have invasion, it doesn’t take much to develop micrometastasis
4 properties of cancer
disease of uncontrolled growth
disease of invasion and metastasis
clonal dominance
loss of differentiation
What is clonal dominance?
cells in a cancer have come from one single ancestral cancer cell
What is tumor heterogeneity?
as tumors grow, mutant subclones are derived - as the tumor grows, it acquires other traits through tumor heterogeneity
**this makes it hard to treat cancer (too many different types of cells)
4 types of cancer therapy
surgery
radiotherapy
chemotherapy
immunotherapy
List 3 limitations in treating cancer
- lack of tumor specific antigen
- tumor cell heterogeneity
- micrometastasis
List some causes of human cancer
environmental carcinogens UV radiation ionizing radiation viruses lifestyle, diet, immune status hereditary factors or genes
How do chemical carcinogens cause cancer?
bind to DNA (electrophile) and form DNA adducts which give rise to mutations; if the mutations occur in “hot spot” genes, then they can be carcinogenic
How does UV/ionizing radiation cause cancer?
chromosome breakage, translocations and point mutations; ACTION IS SIMILAR TO CHEMICAL CARCINOGENS - FORMATION OF DNA ADDUCTS
What genes in HPV are important? What do they do?
E6 and E7; they inactivate tumor suppressors p53 and pRb
How is UV/ionizing radiation different from other chemical carcinogens?
can cause single and double stranded DNA breaks
4 cancers associated with Epstein Bar Virus?
Burkitt’s lymphoma
B cell lymphoma in AIDS pts
Hodgkin’s disease
Nasopharyngeal cancer
Why do immunodeficient hosts have a higher rate of certain cancers, esp virally-induced cancers?
they lack the proper antigen recognition of the viral cells
**immunocompromised pts not necessarily more susceptible to cancers like breast cancer that don’t have an antigenic marker
T/F: Nuns (women who are nulliparous) have a high rate of breast cancer
True
Men who are obese have a higher rate of this cancer
esophageal
Women who eat fatty foods have a higher rate of this cancer
breast
People who eat red meat have a higher incidence of this cancer
colon
Do more cancers have a familial component or inherited component?
familial
**certain cancers run in families
What is the cause of MOST cancers?
spontaneous and sporadic - UNKNOWN CAUSE