Pathogenesis Flashcards
What cancers are classified as head and neck?
mouth
oropharynx
nasopharynx
hypopharynx
nose
paranasal sinuses
larynx
salivary glands
ear
what pathology are most cancers of the head and neck?
squamous cell carcinomas arising from lining mucosa
what are the main aetiologies for head and neck cancer?
tobacco
alcohol
hight risk HPV
EBV
What term describes a genetic disease (abnormal growth that may or may not be cancerous)?
neoplasia
can tumours run in families?
yes
what are the 2 steps in the theory of carcinogens?
initiation - DNA damage and mutation
promotion - clonal expansion of abnormal cells leading to cancer
what type of cells are neoplastic?
- blood vessels
- inflammatory cells
- fibroblasts
- stroma
tumour cells lacking normal control mechanisms leads to?
clone expansion due to uncontrolled proliferation
- replication
- escape from senescence
- evasion of apoptosis
- limitless replicative potential
what is senescence?
growth arrest
what is there a reduction of in invasive growth?
cell-cell adhesion
what is there an invasion of in invasive growth?
basement membrane and stroma
for invasive growth, what must tumour cells be?
motile
what do groups of cells need?
cell-cell adhesion and communication
where do groups of cells predominate?
differentiated carcinomas
in groups of cells, what are inner cells protected from?
immunological assault
what factors do groups of cells require?
autocrine pro-migratory factors and proteolytic enzymes
what is angiogenesis?
formation of new blood vessels
why does a rich blood supply form around a tumour?
loss of control of angiogenic switch
how are tumour blood vessels formed?
outgrowth of endothelial cells from post capillary venules into tumour mass.
what is a critical step in the progression of a small localised tumour to a bigger one with metastatic potential?
angiogenesis
what is metastasis?
tumour implants that are discontinuous with the primary lesions
what event affects tumour stage?
metastasis
where are common sites for metastatic disease?
- Regional lymph nodes
- Liver
- Lung
- Bone
- Brain
- Skin
- Unusual sites – renal cancer, thyroid cancer, melanoma
what are routes of metastasis?
- Lymphatic (carcinoma)
- Haematogenous (sarcoma)
- Across body cavities (serous cavities, meninges/ ventricles/ spinal canal)
- Direct implantation
how do tumour cells reach the site of metastasis?
breach the basement membrane of vessel and enter vessel lumen
bind to endothelial cells, penetrate BM, move out of vessel
what organs are effective at arresting circulatory cancer cells?
lung and liver
what happens before invsive growth?
dysplasia
where does dysplasia occur?
epithelial (squamous and glandular)
what does dysplasia indicate?
risk of developing carcinoma
where are atypical epithelial alterations limited to?
surface squamous epithelium
what are types of atypical epithelial alterations?
architectural and cytological
what is architectural change in epithelial cells?
maturation and differentiation
what is cytological change in epithelial cells?
change in cells
at the point of dysplasia are cells cancerous?
they show features of cancer cells but arent able to invade adjacent normal tissues
what are the histological features of epithelial dysplasia?
- nuclear and cellular pleomorphism
- increase in nuclear/ cytoplasmic ratio
- nuclear hyper chromatism
- prominent nucleoli
- increased and abnormal mitoses
- loss of polarity of basal cells
- basal cell hyperplasia
- drop-shaped rete pegs
- irregular epithelial stratification
- abnormal keratinisation (cells start to keratinize before reaching the surface)
- loss/ reduction of intercellular adhesion
according to WHO 2017 grading, describe mild dysplasia?
disorganisation, increased proliferation, atypia of basal cells
according to WHO 2017 grading, describe moderate dysplasia?
more layers of disorganised basaloid cells, atypia, suprabasal mitoses
according to WHO 2017 grading, describe severe dysplasia?
very abnormal, affects full thickness of epithelium
what does a dyskeratotic cell look like?
hyperchromatic nuclei and/or irregular nuclear chromatin
