Tumour Behaviour

Question 1

why do we get variations in cancer types and subtypes?

Answer 1

varaiation arises from:

1. order mutations occur
2. which mutations occur
   - get parralel pathways existing to create tumoregenic cells

Question 2

is carcinogensis one or multi-step process?

(need to know about adenocarcinoma?)

Answer 2

multi-step process. requires several mutations

Question 3

what are cancer stem cells?

what do their properties depend on?

Answer 3

definition: cells with self renewal potential in order to produce the variety cells that form tumours. (the stem like properties are similar to normal stem cells).

• can self renew OR extensivelly differentiate into a cell type that then propogates additional cancer types
• the proporties of the cancer stem cells depends on the epigenetic changes within genes and RNA transcript

Question 4

what are the two hypothesis for the generation of cancer stems cells?

Answer 4

1. cancer stem cell model
2. clonal evo model

Question 5

explain the cancer stem cell model

Answer 5

1. normal progenitor cell -> can develop into differentiated normal breast cells
2. within tumours / tissues that will become cancerous: abnormal progenitor cells exist. can self-renew.

3. abnormal progenitor cells acquire mutations and ability to proliferate become: mutated progenitor cell

4. mutated progenitor cell self renew and become: cancer stem cell. can also dedifferentiate

5. further mutations: some will become tumour cells, others remain as stem cells

Question 6

explain clonal evolutionary model

Answer 6

clonal evolutionary model

(overview: differentiated mammry cells gain mutations and undergo dedifferentiation process. (NOT PROGENITOR CELLS LIKE LAST H)
- start off as differentiated stem cell and mutation occurs
- after 1st mutation: no longer properly functioning mammary epi. cells. acquires characteristics of mutated stem cell
- after 2nd mutation: forms a cancer cell
- undergoes dedifferentiation: forms cancer stem cell
- cancer stem cell becomes cancer cell or cancer stem cell

Question 7

what are the three critical determinants of tumour classification?

Answer 7

1. differentation state

• epithelial
• non epithelial
• mixed

2. embryonic origin

• ectoderm
• endoderm
• mesoderm

3. biological behaviour

• benign
• malignant

Question 8

epithelial tumours are derived from which germ layers?

connective tissue tumours are derived from which germ layers?

bone tumours are derived from which germ layers?

nervous tumours are derived from which germ layers?

Answer 8

• epithelial tumours dervied from: ectoderm, endoderm and mesoderm
• connective tissue tumours dervied from: mesoderm
• bone tumours dervied from: mesoderm

- nervous tissue tumours dervied from: ectoderm

Question 9

name a epithelial tissue that is derived from each germ layer

Answer 9

(probs just for awareness)

Question 10

what are the two major categories of epithelia that inform what the type of carcinoma (epithelial cancer) will be?

Answer 10

covering and lining epithelia

• e.g. lining of skin / lining of interal organs / forms lining of fucts and body cavities
• stratified squamous

glandular epithelia

e. g. thyroid, adrenal and sweat glands. glands in breast and prostate
- simple cuboidal and simple columnar

Question 11

what are the most common human cancers?

Answer 11

= epithelial in origin

- > 80% cancer related deaths in W. world

Question 12

name the two specific types of carcinoma that are prevalent

Answer 12

1. producing reconizable squamous cells: squamous cell carcinoma - (nasal cavity, larynx, lung, cervix and skin)

2. glandular growth pattern: adenocarcinoma (e.g. lung, colon, breast, pancreas, stomach, prostate)

BUT: IMPORTANT TO NOTE -> IN ONE TISSUE WILL HAVE BOTH TYPES OF EPITHELIAL CELLS: CANCER CAN DERIVE FROM DIFFERENT EPITHELIAL TYPES

Question 13

how do you do nomenclature of a begign tumour?

Answer 13

1. name of cell origin

+

2. morphological character

+

3. • oma (means its benign)
     * e.g squamous cell papilloma*

Question 14

which tissues make mesenchymal / stromal derived tumours?

which tissues make all three germ layer tumours?

Answer 14

Question 15

what are:

• adenomas
• papillomas
• cystadenomas?
• what are polyps?

Answer 15

all: BENIGN EPITHELIAL TUMOURS

adenoma: tumour forming glands

papilloma: tumour with finger-like projections

cystadenoma: cystic tumour

polyp: tumours that projects above mucosal surface

Question 16

how do you name malignant tumours?

Answer 16

1. name of cell origin

+

2. morphological character

+

3. sarcoma / carcinoma (epithelial -> carcinoma, mesenchymal -> sarcoma)

other types of malignant tumours include:
hematopoietic –> leukaemia / lymphoma / myeloma

neuroectodermal –> glioma / neuroblastoma

embryonic –> blastoma

Question 17

name the different types

Answer 17

Question 18

what are the differences between benignn and malignant tumours?

Answer 18

benign

• NOT cancer
• remain localised to tissue from arising tissue
• curable by surgery (by can compress vital organs, but this be highly dangerous depending on region)
• slow growing, grow by expansion

- low mitotic rate

• non-mestastasising
• often encapsulated with capsule. often smooth ./ oval
• well differentiated
• basement membrane not breached

malignant

• ARE cancer
• fast growing, expansoon and infiltration

- high motitic rate

• poorly differentiated
• basement membrane breached
• tumour cells detatch and extent thru adjacent tissues (e.g. blood tissue / lymph)
• if carried away and attach to distant organ: mestastasise
• surgery difficult

Question 19

what are the charcateristics of cancer cells? (4)

Answer 19

• immortal
• high cell division
• ischemic necrosis in middle of tumour -> centre of tumour lacks food / O2 so cells die
• shedding or loss of tumour cells
• Grade 1 -> Grade 3 cancer: cells become less differentiated / undifferentiated

Question 20

what does it mean if cells are becoming undifferentiated?

Answer 20

• become immature
• lose cytoarchitecture of well differentiated tissues
• lose normal function

- rate of growth is directly proportionate to degree of differentation

- (malingant tumours are well differentiated)

Question 22

what are keratin pearls?

Answer 22

• when invading tumour cells retain ability to synthesis keratin - keratin becomes trapped inside the tumour: keratin pearls
• demonstrates still fairly differentiated

Question 23

what is transformation of a cell?

Answer 23

transformation: malignant change in target cell

Question 24

give quick overview of how mestasis occurs

Answer 24

1. vascularisation of tumour occurs
2. cells detach from primary tumour
3. BM is degraded :( and invasion into ECM occurs
4. Intravasation of nearby blood vessels (need to breach membrane of enterocytes to do this)
5. tumour cells circulate in vascualar system
6. some cells adhere to walls of blood vessels
7. Extravasation (leave blood vessels) to local tissues
8. secondary tumour

Question 25

what are the two types of dissemination of mestasis?

Answer 25

1. **haematogenous** dissmination 2. **lymphatic** dissemination

Question 26

where does - colon - breast - prostate cancers often mestasise to?

Answer 26

**distant mesatasis sites :** - colon -\> liver - breast -\> brain - prostate -\> pelvis, spinal cord and ribs

Question 27

why is nodal meatastasis important?

Answer 27

**_significant for:_** - **prognosis** - number of nodes is key - **therapy** - risk of reoccurance, extent of nodal involvement, histological grade, adjuvant therapy

Question 28

where is most common site for breast cancer mestasis?

Answer 28

underarm lymph nodes

Question 29

how do you grade and stage tumours?

Answer 29

_**Grading** depends on:_ 1. **degree of anaplasia** (degree of differentiation) -\> more undifferentated = lower grade 2. **rate of growth** _**Stage** depends on:_ 1. **size of tumour** 2. **spread / extent of tumour**

Question 30

explain what grading I-IV means? what are the two types of staging systems?

Answer 30

Question 31

what are paraneoplastic syndromes?

Answer 31

**- paraneoplastic syndromes:** clinical syndromes not caused by direct invasion or metastasis of tumour which accompany malignant disease. non-metastatic manifestation of malignant disease - associated with malignancies in: **lung, breast, gynaecologica and haemotoligcal tumours** - arise from tumour secretion of **hormones, peptides, cytokines** -\> interfere with normal metabolic pathways of hormones peptides

Question 32

what are the four categories of paraneoplastic syndromes?

Answer 32

1. endocrine 2. neurologic 4. dermatologic & rheumatologic 5. hematologic

Question 33

give summary of why paraneoplastic syndromes cause symptoms

Answer 33

series of tumours within specific tissues (e.g. endocrine / gynanelgoical tissues). result in excess secretion of bioactive molecules. in turn cause condition NOT directly associated with primary tumour. instead associated with excess of hormone / or cytokine etc

Question 35

whar are the terms need to know for origins of tumour?

Answer 35

In terms of the origin of the tumour, there are only 2 broad types you need to know: **Epithelial tumours** involves **stratified squamous, simple cuboidal and simple columnar.** - _Stratified squamous_ e.g. skin, lining of respiratory tract, upper oesophagus, cervix - _Cuboidal and columnar_ e.g. adrenal gland, sweat gland, pancreatic ducts, stomach, etc. – these are cells that secrete things **Mesenchymal** is pretty much any other tissue type E.g. bone, cartilage, nervous tissue, etc.