carcinogenesis

Question 1

what is carcinogenesis?

Answer 1

The transformation of normal cells to neoplastic cells though permanent genetic alterations or mutations
- a multistep process

Question 2

what are carcinogens ?

Answer 2

Agents known or suspected to cause tumours

Question 3

describe the term carcinogenic

Answer 3

cancer causing

Question 4

describe the term oncogenic

Answer 4

tumour causing

Question 5

what in the environment may cause cancer?

Answer 5

85% of cancer is risk is environmental
PROBLEMS
Latent interval may last decades
Complexity of environment
Ethical constraints

Question 6

occupation/behavioural risks- lung cancer

Answer 6

strong association with smoking

Question 7

occupation/behavioural risks- bladder cancer

Answer 7

increased incidence in aniline dye and rubber

Question 8

occupation/behavioural risks- scrotal cancer

Answer 8

increased incidence in chimney sweeps

Question 9

where is Hepatocellular carcinoma common/uncommon?

Answer 9

-Uncommon in UK/USA
-Common in areas with ↑ Hepatitis B/C and mycotoxins

Question 10

where is oesophageal carcinoma common/uncommon?

Answer 10

↑↑ incidence in Japan, China, Turkey and Iran
? Dietary factors (Linhsien chickens)

Question 11

what are the classes of carcinogens

Answer 11

• chemical
• viral
  -ionising and non ionising radiation
  -hormones, parasites and mycotoxins
  -miscellaneous

Question 12

classes of carcinogens- chemical

Answer 12

No common structural features
Some act directly
Most require metabolic conversation from pro-carcinogens to ultimate carcinogens
Enzyme required may be ubiquitous or confined to certain organs

Question 13

classes of carcinogens- ionising and non ionising radiation

Answer 13

Exposure to UVA or UVB
Ionising radiation
Long term effect
Skin cancer in radiographers
Lung cancer in uranium miners
Thyroid cancer in Ukrainian children

Question 14

what are host factors?

Answer 14

things you can’t change

Question 15

name 5 host factors

Answer 15

• race
  -diet
• constitutional factors- age, gender
• premalignant conditions
  -transplacental exposure

Question 16

host factors- race

Answer 16

Decreased skin cancer in black people (melanin)
Increased oral cancer in India, SE Asia (reverse smoking)

Question 17

host factors- constitutional factors

Answer 17

Inherited disposition
Age – incidence increases with age
Gender – breast cancer F:M = 200 (more common in women)

Question 18

host factors- premalignant conditions

Answer 18

Identifiable local abnormality associated with increased risk of malignancy at that site e.g. colonic polyps, undescended testis, cervical dysplasia