Cancer

Question 1

How cancer develops

Answer 1

Carcinogen (something that starts the cancer process, almost always environmental) damages DNA

Programs gene, gene = subject to mutation

Cell loses ability self-destruct, replicates uncontrollably –> mass of abnormal tissue

Question 2

Characteristics of normal mammalian cells

Answer 2

Anchorage dependence: won’t divide unless touching something

Density-dependent inhibition: cells will fill gap and stop at one layer

Question 3

Characteristics of cancer cells

Answer 3

Do NOT have anchorage dependence/density-dependent inhibition

Can make their own growth factor (food)…can divide without an energy base/can convey growth factor’s signal without presence of growth factor

Question 4

Transformation

Answer 4

Normal cell converted to a cancerous cell - cancer cells form tumors (masses of abnormal cells within otherwise normal tissue)

Question 5

Benign vs. Malignant

Answer 5

Benign: NOT cancer - when abnormal cells remain at original site
Malignant: tumors invade surrounding tissues and can metastasize (export cancer cells to other parts of the body to form secondary tumors)

Question 6

Cancer development

Answer 6

Normal cells
Initiation (introduction of carcinogen)
Carcinogen alters DNA, inducing abnormal cell division
Promotion: enhance development of abnormal cells, resulting in tumor
Further tumor development
Metastasis (cells released into bloodstream/lymphatic system)

Question 7

Henrietta Lacks

Answer 7

Died of cervical cancer, doctors kept her tumor
Immortal cell line: cells still dividing today, used to test medication for cancer/AIDS/polio, etc

HeLa cells

Question 8

Lung cancer

Answer 8

Small cell/non small cell
Fairly deadly (70% mortality rate)
80-90% due to tobacco (others = radon, asbestos, air pollution)
Consequences: coughing up blood, shortness of breath, weight loss
How to diagnose: chest radiograph, biopsy

Question 9

Pancreatic Cancer

Answer 9

85% mortality rate
Very aggressive, usually found in advanced stages
Greatest risks: African Americans, men, old age; smoking, diabetes

Question 10

Breast Cancer

Answer 10

Signs: lump, nipple inversion/discharge
How to find it: mammogram, self exams, ultrasound, biopsies
Risk factors
-incidence doubles every 10 years until menopause, then drops off
-hormone replacement therapy, BMI, alcohol, BPA, radiation

Genetics = 5-10% (BRCA 1 and BRCA 2, first degree relative)
Environmental = 90 - 95%

Question 11

Ovarian Cancer

Answer 11

Hard to diagnose, causes unknown
Risk factors: infertility, BRCA, milk?
Protective factors: birth control, tubal ligation, vitamin D

Question 12

Cancer treatments

Answer 12

Surgery: remove tumors/determine extent of cancer BUT raises energy/protein needs
Chemo: inhibits tumor growth BUT has toxic effects
Radiation: damages DNA of cancer cells/leads cells to death, shrinks tumors
Bone marrow transplants
Immunotherapy: stimulate immune system

Question 13

Skin cancer and forms

Answer 13

1/5 americans will develop skin cancer in their lifetime; most common in US by a long shot

Basal cell carcinoma
Squamous cell carcinoma
Melanoma

Question 14

BCC

Answer 14

Basal cell Carcinoma

• most common form of skin cancer
• appears on sun-exposed areas of body (face, neck, arms)
• often presents as a persistent, non-healing sore

Question 15

SCC

Answer 15

Squamous cell carcinoma

• 2nd most common skin cancer
• .3% mortality rate
• appears on sun-exposed areas
• presents as scaly, red, hard nodules that usually ulcerate/may bleed

Question 16

Melanoma

Answer 16

5% of skin cancer causes, but vast majority of death bc of rapid metastasis
Stages
-stage 0: carcinoma “in-situ” localized/non invasive (99% survival)
-stage 1/2: localized lesions that have not spread beyond original site (95% survival)
-stage 3: tumor spreads beyond original site to regional lymph nodes (24-70% survival)
-stage 4: metastasis to distant lymph nodes/internal organs, affect internal organs (7-19% survival)

Question 17

UVR

Answer 17

Ultraviolet Radiation 
UVA rays cause aging
-less intense, but more prevalent
-deep penetration of skin
-equal intensity during all daylight hours
-can penetrate clouds/glass 
UVB rays cause burning
-cause superficial skin damage
-10AM - 2PM = peak intensity

Question 18

UVR and cancer types

Answer 18

BCC: intermittent UVR (recreational exposure = children playing outside)
SCC: chronic UVR (occupational exposure = construction workers)
Melanoma: intermittent UVR

Question 19

Tanning beds

Answer 19

UVA radiation
75% more likely to develop melanoma when use starts before age of 35
2.5X more likely to develop BCC, 1.5X more likely to develop SCC

Question 20

Genetic predisposition to skin cancer

Answer 20

Skin phenotype: melanin absorbs UV radiation, fair skin = less melanin
Family history: CDKN2A gene associated with melanoma
Numerous/atypical moles

Question 21

ABCDE’s of moles

Answer 21

Asymmetry
Border (uneven)
Color (multipole colors)
Diameter (larger than 1/4 inch)
Evolution (changing in size/color/shape)

Question 22

Sunscreen

Answer 22

SPF = sun protective factor, indicates how long it will take for UVB rays to redden skin when using product

SPF 15 = 93% of UVB rays
SPF 30 = 97% of UVB rays
SPF 50 = 98% of UVB rays

Broad/multi-spectrum protects from UVB AND UVA rays
Reapply every 2 hours