-
New skin cancers each year (from sun UV)
1.5m
-
Types of skin cancer
- Basal cell carcinoma
- Squamous cell carcinoma
- Melanoma
-
Squamous cells are closer to the surface than basal cells (T/F)
T
-
Skin cancer development depends on...
-
Moh's surgery
Removal of skin cancer in layers
-
Basal cell carcinoma rate and metastasis rate
- 75% of skin cancers
- 1/1000 metastisize
-
Squamous cell carcinoma rate and metastasis rates
- 20% of skin cancers
- 1/20 metastisize
-
Melanoma rate and death rate
- 5% of skin cancers
- 80% of cancer deaths
-
Nonmelanoma cancers
Basal and squamous cell carcinomas
-
Skin anatomy (from surface down)
- Dermis
- Epidermis
- Stratum basale (epidermis) - BCC
- Strateum corneum (epidermis)
-
Types of UV radiation
- UV-A, 400-315nm
- UV-B, 315-280nm
- UV-C, 280-100nm
-
UV (types) absorption in the ozone layer
- All UV-C
- Most UV-B
- Little-to-no UV-A
-
Type of UV responsible for sunburns
UV-B
-
Type of UV for cleaning things
UV-C
-
Light absorbed by DNA
~260nm
-
Common DNA adducts resulting form UV
- Cyclobutyl pyrimidine dimers
- 6-4 photoproducts
-
Most sensitive bases to UV
Pyrimidines
-
6-4 Photoproduct
Pyrimidine O4 reacts with adjacent pyrimidine C6
-
Relative rates of skin cancers, with UV type
- UV-A: 1
- UV-B: 1000x (UV-A)
- UV-C: 100,000x
-
Most common exposure to UV-C
Germicidal lamps
-
Two outcomes from a pyrimidine dimer
- NER
- Replicaiton/misreading (Read as CC instead of TT for example)
-
CC->TT mutation in internal tumors
Rate, closely related to UV
-
Why does UV affect the initiation stage of synthesis
- It causes TT->CC mutations in p53
- Inactivates p53
-
Role of p53
- Protect cell from UV damage
- Induce cell cycle arrest (await repair)
- Initiate apoptosis
-
Subsequent burns are a...
promoter
-
Types of sunscreen
- Physical (Reflect): ZnO, TiO2
- Chemical (Absorb): Para aminobenzoic acid
-
UV-B absorbing compounds
Cinnamates, salicylates, octocrylene
-
UV-A absorbing compounds
Benzophones, Avobenzone
-
Cells producing melanin
Melanocytes
-
Risk increase with tanning bed use (under 30)
- 75%
- 8x more likely to get melanoma
-
Reasons tanning beds are worse than solar radiation
- Intensity
- Greater penetration
- UVA/UVB ratio
- Reduced burning
-
Two ways ionizing radiation can mutate DNA
- Strip electrons
- Create wate-based radicals
-
Ionizing radiation radicals
-
Who discovered X-rays
Wilhelm Roentgen
-
Who discovered radioactivity, when?
-
Radioactive elements
Promethium, technetium and elements heavier than polonium
-
Ways of measuring radiation dose
- Electron volt - Measure of energy, not common
- Gray/Rad - Energy absorbed by a tissue
- Sievert - Product of Gray and biological effect (1-20)
-
Radon
- Gas produced from decaying uranium
- Decays relatively quickly into polonium particles (alpha emitter)
-
Amount of ionizing radiation exposure attributable to radon
54%
-
-
Cobalt bomb
Using directed radiation to target tumors
-
Living labs
- Hiroshima (and nagasaki) - Radiation
- Chernobyl - Radiation
- Fukushima - Radiation
- Lower Manhattan - Asbestos
-
Cancer associated with nuclear fallout
- Thyroid
- From radioactive iodine buildup
|
|
