8 Neoplasia 1 & 2

Question 1

Define Tumour

Answer 1

Detectable lump or swelling

Question 2

Define Neoplasm

Answer 2

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

Question 3

Define Metastasis

Answer 3

Malignant neoplasm that has spread from its original site to a new non-contiguous site

Question 4

Define Dysplasia

Answer 4

A pre-neoplasticism alteration in which the cells show disordered tissue organisation

-reversible

Question 5

How is Dysplasia exhibited microscopically

Answer 5

Pleomorphism
Large hyperchromatic nuclei
High nuclear:cytoplasmic ratio

Question 6

Describe primary and secondary site in neoplasm

Answer 6

Primary: original location of the malignant neoplasm
Secondary: the place to which the malignant neoplasm has spread

Question 7

Describe the difference between Benign and Malignant neoplasm in terms of behaviour and histology

Answer 7

Benign:
(B) expansive growth locally, retained original functions of cells

(H) resembles cells of origin, few mitoses, normal in nuclear:cytoplasmic ratio, cells are uniform throughout tumour

Malignant:
(B) expansive, invasive, potential to metastasise, less likely to retain original function, acquire unexpected functions

(H) failure to differentiate fully, abnormal form of mitoses, high nucleus:cytoplasmic, pleomorphism

Question 8

How is the degree of differentiation classified

Answer 8

Grade is an indicator of differentiation of the cell

High grade = Poorly differentiated

Question 9

How does neoplasia occur

Answer 9

1. Exposure to carcinogens causes non-lethal genetic damage
2. Accumulated mutations in somatic cells
3. Mutations are caused by initiators (mutagenic agents)
4. Promoters cause cell proliferation
5. Tumour is formed by clonal expansion of a single precursor cell that has incurred genetic damage

Question 10

Examples of Initiators

Answer 10

Chemicals (smoking, alcohol consumption, diet)
Infectious agents (HPV)
Radiation
Inherited mutations (BRAC I & II)

Question 11

What are the four classes of normal regulatory genes

Answer 11

Growth promoting proto-oncogenes
Growth inhibiting tumour suppressor genes
Genes that regulate apoptosis
Genes involved in DNA repair

Question 12

Describe Proto-Oncogenes and its functions

Answer 12

Function: Involved in signalling pathways and drives proliferation

Question 13

What can mutation in a proto-oncogene lead to

Answer 13

Conversion to Oncogene and can subsequently activate it to become an Oncoprotein permanently

Question 14

Functions of Tumour Suppressor Genes.

Answer 14

Stop cell proliferation

Question 15

What can mutation to Tumour Suppressor Genes lead to

Answer 15

Stop cell proliferation
-causes ‘loss-of-function’
-both alleles must be damaged for transformation to occur
-failure of growth inhibition

Question 16

Example of Tumour Suppressor Genes

Answer 16

TP53 gene
-codes for protein P53 which directs apoptosis, repair
-‘guardian of the genome’

Question 17

Function of Apoptosis Regulating Genes

Answer 17

Regulate cell death and survival of cells

Question 18

Mutation of DNA Repair Genes results in

Answer 18

-loss of function mutations
-impair ability of cell to recognise and repair non-lethal genetic damage in other genes

Mutator phenotype: A stage where affected cells acquire mutations at an accelerated rate
-marked by genomic instability

Question 19

Pattern/rule in naming Neoplasms

Answer 19

Benign tumours:
ends in -oma
Malignant tumours:
End in carcinoma, sarcoma

Question 20

Examples of epithelial neoplasm (Benign & Malignant)

Answer 20

Benign:
Squamous papilloma, Transitional cell papilloma, Adenoma, Cystadenoma

Malignant:
Squamous cell carcinoma, Transitional cell carcinoma, Adenocarcinoma

Question 21

Check table with tissue of origin and its term for benign and malignant tissue

Question 22

Define Invasion

Answer 22

Breach of the basement membrane with progressive infiltration and destruction of the surrounding tissues

Question 23

Define Metastasis

Answer 23

Spread of tumour to sites that are physically discontinuous from the primary tumour

Question 24

Describe the process that leads to metastasis

Answer 24

1. Grow and invade at the primary site
2. Enter a transport system and lodge at a secondary site
3. Grow at the secondary site to form a new tumour (colonisation)

Question 25

Describe the alteration needed for invasion

Answer 25

Altered adhesion:
-reduction in E-Catherine expression,changes in Integrin expression

Stromal proteolysis:
-altered expression of predates, matrix metalloproteinases (MMPs)
-nearby non-neoplastic cells provides GF and proteases

Motility:
-changes in actin cytoskeleton

Question 26

What is mesenchymal transition and when does this happen

Answer 26

When cell takes on a phenotype more akin to mesenchymal cell than an epithelial cell