15. Neoplasia Flashcards
Benign neoplasm
Local expansile growth only
Resembles cell of origin
Few mitoses
Normal nuclear: cytoplasmic ratio
Cells are uniform throughout the tumour
Hyperchromatism
Malignant tumour
Expansile and invasive growth
May metastasise
Failure of differentiation
Many mitoses
High nuclear: cytoplasmic ratio
Cellular + nuclear polymorphisms
hyperchromatism
Nomenclature of malignant tumours
end in ‘sarcoma’ or ‘carcinoma’
Nomenclature of benign tumours
end in ‘oma’ or ‘myoma’
Well Differentiated
resembles tissue of origin
Poorly Differentiated
little or passing resemblance to tissue of origin
Anaplastic
no resemblance to tissue of origin = complete failure of differentiation
Teratomas
hair and sebaceous glands
teeth
skin
4 main routes malignant neoplasms can metastasise
Local invasion
Lymphatic spread
Vascular spread
Trans-coelomic spread
Trans-coelomic spread
pleural cavity
Invasion of lymphatics
tumour (T) may grow into and along lymphatics
fragments can break free and travel along vessels to nodes
Main sites of blood borne metastases
Brain and CSF
Lung
Liver
Adrenals
Bone
TNM staging
T = 1° tumour
Number denotes size and extent
N = lymph node involvement
M = extent of different metastases
Duke’s staging
Duke’s A - spread into submucosa but not through muscle
Duke’s B - spread through muscle but nodes negative
Duke’s C - lymph node metastases present
Molecular causes of neoplastic changes
1) Point mutations
2) Gene amplification
3) Chromosomal rearrangements
Mitogens
control rate of cell division by acting on G1 phase
Problems with the Treatment of Cancer
Doubling times
Solid tumours
Cytotoxic drugs = adverse/side effects
p53 gene
mutated in half all human cancers
normally present in very small quantities
Blocks entry to S phase
Approaches to cancer therapy
Kill or remove malignant cells
Inactivate oncogene signalling pathways
Proliferation inhibitors
Side effects of cytotoxic drugs
Impaired wound healing
Alopecia
Gastrointestinal epithelial damage
Growth depression – children
Sterility
Nausea and vomiting
Oral mucositis
Alkylating agents
Form carbonium ions
Interferes with: Transcription + Replication – S Phase
