Tumour Behaviour Flashcards
why do we get variations in cancer types and subtypes?
varaiation arises from:
- order mutations occur
-
which mutations occur
- get parralel pathways existing to create tumoregenic cells
is carcinogensis one or multi-step process?
(need to know about adenocarcinoma?)
multi-step process. requires several mutations
what are cancer stem cells?
what do their properties depend on?
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
what are the two hypothesis for the generation of cancer stems cells?
- cancer stem cell model
- clonal evo model
explain the cancer stem cell model
- normal progenitor cell -> can develop into differentiated normal breast cells
- 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
- 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
explain clonal evolutionary model
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
what are the three critical determinants of tumour classification?
1. differentation state
- epithelial
- non epithelial
- mixed
2. embryonic origin
- ectoderm
- endoderm
- mesoderm
3. biological behaviour
- benign
- malignant
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?
- 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
name a epithelial tissue that is derived from each germ layer
(probs just for awareness)
what are the two major categories of epithelia that inform what the type of carcinoma (epithelial cancer) will be?
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
what are the most common human cancers?
= epithelial in origin
- > 80% cancer related deaths in W. world
name the two specific types of carcinoma that are prevalent
- 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
how do you do nomenclature of a begign tumour?
- name of cell origin
+
- morphological character
+
- oma (means its benign)
* e.g squamous cell papilloma*
- oma (means its benign)
which tissues make mesenchymal / stromal derived tumours?
which tissues make all three germ layer tumours?
what are:
- adenomas
- papillomas
- cystadenomas?
- what are polyps?
all: BENIGN EPITHELIAL TUMOURS
adenoma: tumour forming glands
papilloma: tumour with finger-like projections
cystadenoma: cystic tumour
polyp: tumours that projects above mucosal surface
how do you name malignant tumours?
- name of cell origin
+
- morphological character
+
- sarcoma / carcinoma (epithelial -> carcinoma, mesenchymal -> sarcoma)
other types of malignant tumours include:
hematopoietic –> leukaemia / lymphoma / myeloma
neuroectodermal –> glioma / neuroblastoma
embryonic –> blastoma
name the different types
what are the differences between benignn and malignant tumours?
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
what are the charcateristics of cancer cells? (4)
- 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
what does it mean if cells are becoming undifferentiated?
- 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)
what are keratin pearls?
- when invading tumour cells retain ability to synthesis keratin - keratin becomes trapped inside the tumour: keratin pearls
- demonstrates still fairly differentiated
what is transformation of a cell?
transformation: malignant change in target cell
give quick overview of how mestasis occurs
- vascularisation of tumour occurs
- cells detach from primary tumour
- BM is degraded :( and invasion into ECM occurs
- Intravasation of nearby blood vessels (need to breach membrane of enterocytes to do this)
- tumour cells circulate in vascualar system
- some cells adhere to walls of blood vessels
- Extravasation (leave blood vessels) to local tissues
- secondary tumour
what are the two types of dissemination of mestasis?
- haematogenous dissmination
- lymphatic dissemination
where does
- colon
- breast
- prostate
cancers often mestasise to?
distant mesatasis sites :
- colon -> liver
- breast -> brain
- prostate -> pelvis, spinal cord and ribs
why is nodal meatastasis important?
significant for:
- prognosis - number of nodes is key
- therapy - risk of reoccurance, extent of nodal involvement, histological grade, adjuvant therapy
where is most common site for breast cancer mestasis?
underarm lymph nodes
how do you grade and stage tumours?
Grading depends on:
- degree of anaplasia (degree of differentiation) -> more undifferentated = lower grade
- rate of growth
Stage depends on:
- size of tumour
- spread / extent of tumour
explain what grading I-IV means?
what are the two types of staging systems?
what are paraneoplastic syndromes?
- 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
what are the four categories of paraneoplastic syndromes?
- endocrine
- neurologic
- dermatologic & rheumatologic
- hematologic
give summary of why paraneoplastic syndromes cause symptoms
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
whar are the terms need to know for origins of tumour?
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.
