Neoplasm

Question 1

Neoplasm definition

Answer 1

An abnormal growth of cells that persists after the initial stimulus is removed

Question 2

Malignant neoplasm definition

Answer 2

An abnormal growth of cells that persists after the initial stimulus is removed AND invades surrounding tissue with potential to spread to distant sites

Question 3

Cancer definition

Answer 3

Malignant neoplasm

Question 4

Metastasis definition

Answer 4

A malignant neoplams that has spread from its original site to a new non contiguous site

Question 5

Dysplasia definition

Answer 5

Pre neoplastic alteration in which cells show disordered tissue organisation. It is not neoplastic because the change is reversible

Question 6

Benign tumour appearance

Answer 6

Grow in a confined local area and so have a pushing outer margin

Question 7

Malignant tumour appearance

Answer 7

Have an irregular outer margin and shape and may show areas of necrosis and ulceration

Question 8

Benign neoplasm under the microscope

Answer 8

Cells that closely resemble the parent tissue, i.e. are well differentiated

Question 9

Malignant neoplasm under the microscope

Answer 9

Range from well to poorly differentiated. Cells with no resemblance to any tissue are called anaplastic. (Malignant tumours ccan be well differentiated)

Question 10

Worsening differentiation under the microscope

Answer 10

Increasing nuclear size, increased nuclear to cytoplasmic ratio, increased nuclear staining (hyperchromasia), more mitotic figures, increasing variation in size and shape of cells and nuclei (pleomorphism)

Question 11

High grade means

Answer 11

Poor differentiation

Question 12

What are initiators ands promoters?

Answer 12

Initiators are mutagenic agents

Promoters cause cell proliferation

Question 13

Invasion into surrounding tissue by carcinoma cells requires:

Answer 13

Altered adhesion, stromal proteolysis, motility

Question 14

Industrial carcinogen used in dye manufacture

Answer 14

2-napthylamine

Question 15

What did malignant neoplasms caused by 2-napthylamine show?

Answer 15

1) There is a long delay between carcinogen exposure and malignant neoplasm onset
2) The risk of cancer depends on total carcinogen dosage
3) There is sometimes organ specificity for particular carcinogens

Question 16

What does the Ames test show

Answer 16

Initiators are mutagens, while promoters cause prolonged proliferation in target tissue

Question 17

How can mutagenic chemical carcinogens be classifies?

Answer 17

• Polycyclic aromatic hydrocarbons
• Aromatic amines
• N nitroso compounds
• Alkylating agents
• Natural products

Question 18

What are pro-carcinogens?

Answer 18

Chemicals that are only converted to carcinogens by cytochrome P450 enzymes in the liver

Question 19

What are complete carcinogens?

Answer 19

Carcinogens that act as both initiators and promoters

Question 20

How do infections affect tissue growth?

Answer 20

• Directly affect genes
• Indirectly by causing chronic issue injury where the resulting regeneration acts either as a promoter for any pre existing mutations or causes new mutations from DNA replication errors

Question 21

How does HPV cause neoplasia?

Answer 21

• Direct carcinogen
• Expresses E6 > inhibits p53
• Expresses E7 > inhibits pRB
• Both are important in cell proliferation
• HPV strongly linked to cervical carcinoma

Question 22

How do Hep B and C cause neoplasia?

Answer 22

Indirect carcinogens that cause chronic liver cell injury and regeneration

Question 23

Which bacteria and parasites increase the risk for the development of carcinomas?

Answer 23

• Helicobacter pylori (chronic gastric inflammation)

- Parasite flukes (inflammation in the bile ducts and bladder mucosa)

Question 24

How does HIV increase risk of neoplasia?

Answer 24

Acts indirectly by lowering immunity and allowing potentially carcinogenic infections to occur

Question 25

First human oncogene discovered

Answer 25

RAS

• Mutated in a third of all malignant neoplasms
• Encodes a small G protein that relays signals into the cell that eventually pushes the cell past the cell cycle restriction point
• RB inhibits passage through restriction point

Question 26

What do proto-oncogenes encode?

Answer 26

• Growth factors
• Growth factor receptors
• Plasma membrane signal transducers
• Intracellular kinases
• Transcription factors
• Cell cycle regulators
• Apoptosis regulators
  (Tumour suppressor genes encode proteins in the same pathways but with anti growth effects)

Question 27

Xeroderma pigmentosum

Answer 27

• Autosomal recessive
• Due to a mutation in one of the 7 genes that affect DNA nucleotide excision repair
• Patients very sensitive to UV damage and develop skin cancer at a young age

Question 28

Hereditary non-polyposis colon cancer (HNPCC) syndrome

Answer 28

• Autosomal dominant
• Associated with colon carcinoma
• Germline mutation affects one of several DNA mismatch repair genes

Question 29

BRCA1 AND BRCA2

Answer 29

Important for repairing double strand DNA breaks

Question 30

Nucleotide excision repair: Inherited syndrome, effector genome

Answer 30

Xeroderma pigmentosa

Nuclear instability

Question 31

Mismatch repair: Inherited syndrome, effector genome

Answer 31

Hereditary non polyposis colon cancer (HNPCC)

Microsatellite instability

Question 32

Double strand break: Inherited syndrome, effector genome

Answer 32

Breast/ovarian cancer

Chromosomal instability

Question 33

Cancer progression

Answer 33

• Early adenoma
• Intermediate adenoma
• Late adenoma
• Carcinoma
• Metastasis

Question 34

Six hallmarks of cancer

Answer 34

1) Self sufficiency in growth signals
2) Resistance to growth stop signals
3) No limit on the number of times a cell can divide
4) Sustained ability to induce new blood vessels
5) Resistance to apoptosis
6) Ability to invade and produce metastases