TUMORS

Question 1

Define tumor

Answer 1

abnormal tissue mass whose growth is uncontrolled and uncoordinated with normal tissue

Question 2

Are tumours reversible?

Answer 2

not reversible

Question 3

What happens if tumours are not treated?

Answer 3

> progress into malignant tumour

> leading to complication and death

Question 4

What is carcinogenesis?

Answer 4

> causes of neoplasia

Question 5

Outline characteristics of malignant tumour?

Answer 5

> reoccurrence
metastasise
haemorrhage
necrosis

Question 6

Define neoplasia?

Answer 6

new growth

Question 7

define tumour?

Answer 7

> swelling
lump
inflammation

Question 8

Give examples of normal new cell growth not related to neoplasm (tumour) ?

Answer 8

> embryogenesis
regeneration/ repair
hyperplasia
hormonal stimulation

Question 9

What do neoplastic cells loose?

Answer 9

> loose control > uncontrolled growth

> loose regulation of replication > abnormal division

Question 10

Requirements for tumour growth (autonomy) ?

Answer 10

> produce their own bloodstream

> nutrients from macro-organism (host)

Question 11

Outline a special biochemical feature of tumours?

Answer 11

> anaerobic glycolysis

> secretion of abnormal about of hormones

Question 12

Why do tumours need anaerobic glycolysis ?

Answer 12

> aerobic glycolysis only produce 2 ATP
not enough
produce more lactic acid > undergoing anaerobic glycolysis
producing more ATP energy

Question 13

Give an example of abnormal amount of hormone secretion by tumours? Explain its effect.

Answer 13

> parathyroid adenoma
PTH
hyperparathyroidism
Ca-P disorders

Question 14

Outline function feature of benign tumour and malignant tumour?

Answer 14

BENIGN TUMOUR
> increased activity

MALIGNANT TUMOUR
> altered > preserve activity

Question 15

What is paraneoplastic syndrome? Give an example.

Answer 15

> group of disorders triggered by abnormal immune system response to a tumour
when cancer fighting WBC + Abs start attacking normal cells

EXAMPLE
> THROMBOPHLEBITIS

Question 16

What is thrombophlebitis?

Answer 16

> inflammatory process due to tumour

> cause blood clotting + block veins (legs)

Question 17

What are tumour synthesises substances? Why are they clinically important? Example?

Answer 17

> tumour markers
can be used for diagnosis
e.g&raquo_space; alpha-fetoprotein in hepatocellular carcinomas

Question 18

Which type of tumour cause more effect in P?

Answer 18

> malignant tumour

Question 19

Outline clinical effects of neoplasia?

Answer 19

> local effect
cancer cachexia
fever
paraneoplastic syndromes

Question 20

Is local effect found in both types of tumour? Outline local effects of tumour?

Answer 20

> found in both benign + malignant

CAUSE LOCAL EFFECT DUE TO:
> size and localisation
> compression of nearby tissue
> mechanical obstruction
> tissue destruction 
> infarction (necrosis due to lack of blood supply)
> ulceration 
> hemorrhage

Question 21

Outline cancer cachexia of tumour?

Answer 21

> “cancer anorexia”

> anorexia and asthenia (no physical energy) together

> loss of fat + muscle due to chronic cancer

Question 22

Outline fever of tumour?

Answer 22

> tumour cells
elaborate pyrogens
causing fever

Question 23

Outline paraneoplastic syndrome of tumour?

Answer 23

> group of conditions developing in advance cancer

> not explained by direct and distant spread of tumour

> abnormal immune system response affected by tumours

Question 24

What are impacts on body of tumours?

Answer 24

> deformations 
> compressions
> pain
> necrosis
> anaemic syndrome 
> suppressed immunity 
> cachexia

Question 25

What are most common cancers in men?

Answer 25

> prostate > lung > colon > testes

Question 26

What are most common cancers in female?

Answer 26

> breast > uterus > ovaries

Question 27

Outline pathogenesis of neoplasia?

Answer 27

1) viral genetic theory 2) physiochemical theory 3) dysontogenetic theory 4) polyetiological theory

Question 28

Outline factors leading to tumours?

Answer 28

> physical carcinogenesis (ionising radiation) > chemical carcinoggenisis ( smoke/ chemical exposure) > viral carcingogenisis (hepatitis, papilloma) > genetic factors (oncogenes)

Question 29

Outline cancers caused by ionising radiation? | .

Answer 29

> skin cancer > acute/ chronic leukaemia > neoplasm of hematopoeisis > thyroid cancer > bone cancer

Question 30

Outline physical factors causing cancer?

Answer 30

> heat - overuse of hot drinks - throat + oesophagus cancer > UV - skin cancer (common in light skin => dark skin have melanin protecting from UV) - facial cancer

Question 31

Degree of skin cancer risk of UV exposure depends on?

Answer 31

> type of UV > intensity of exposure > quantity of UV absorbed > protective mantle of melanin in skin

Question 32

Outline types of UV? | Which is most cancerous UV for skin?

Answer 32

> UV A > UV B > UV C UV B - most cancerous for skin cancer

Question 33

How does UV B cause cancer in cells?

Answer 33

> causes formation of pyramiding dimers in DNA > this DNA damage is repaired by nucleotide excision repair pathway > 5 steps in nucleotide excision repair pathway > with excessive UVB exposure - nucleotide excision repair pathway becomes overwhelmed > error-prone non templated DNA repair mechanism is operative >> leading to survival of cancerous cells

Question 34

Outline the steps involved in chemical carcinogenesis?

Answer 34

> initiation step | > promotion step

Question 35

Explain initiation step of chemical carcinogenesis?

Answer 35

changes genes > becoming oncogenes > exposure of cells to sufficient dose of carcinogenic agents > initiated cells = altered > permanent DNA damage > potential tumour tumor suppressor genes > P53 > RAS > MYC

Question 36

Explain promotion step of chemical carcinogensisi?

Answer 36

activation of altered genes > promoters induce tumours in initiated cells > promoters are not tumorigenic themselves > promoters only cause tumour if cell undergone initiation step > promoters do not cause tumours directly PROMOTERS: > hormones > esters > phenols

Question 37

Why are chemical carcinogens highly reactive?

Answer 37

> highly reactive electrophiles (electron deficient) > react with nucleophilic (electron rich) sites of cells - DNA - RNA - proteins this highly active reaction can lead to death

Question 38

Outline a hormone involved in chemical carcinogensisi?

Answer 38

OESTROGENS > breast cancer > endometrium cancer > benign myometrial tumours

Question 39

What is aflatoxin B?

Answer 39

> substance produced by fungi grown on grains and nuts not stored properly > causing cancer

Question 40

Define oncogenes?

Answer 40

genes that stimulate autonomic growth of tumour cells

Question 41

Define protooncogenes?

Answer 41

> normal genes requires for normal cell divines | > can mutate to become oncogenes and stimulate tumour

Question 42

What activates oncogenes and protooncogenes?

Answer 42

> point mutation > translocation > amplification

Question 43

What is p53 gene?

Answer 43

> found in normal cell cycle which control normal cell division > mutation in p53 leads to abnormal proliferation of cells causing cancer

Question 44

What are tumour markers?

Answer 44

> oncoprotein or mutated forms of proteins > indicating presence of tumour

Question 45

What is oncoprotein?

Answer 45

> product of mutated oncogenes | > regulate proteins linked to tumour cells

Question 46

Which are most important cancer forming substance in cigar smoke?

Answer 46

> tar > benzopyrene > anthracene

Question 47

What is anthracosis and how does it look on on lungs?

Answer 47

> chronic lung disorder with deposition of coal and carbon in lung parenchyma leading to formation of black nodules and emphysema > black spots on lungs