cancer Flashcards
what is carcinogenesis?
The transformation of normal cells to neoplastic cells through permanent
genetic alterations or mutations
what is a neoplasm?
A lesion resulting from the autonomous or relatively autonomous abnormal
growth of cells which persists after the initiating stimulus has been removed - a
new growth
what is a tumour?
any abnormal swelling
what is a benign neoplasm?
- localised
- slo growth rate
- non-invasive
- well-differentiated
how can benign tumours still cause morbidity and mortality?
- pressure on adjacent structures
- obstruction to the flow of fluid
- production of a hormone
- transformation into a malignant neoplasm
what are malignant neoplasms?
- invasive
- rapidly growing
- irregular border
- do not resemble parent cell
- poorly differentiated
- hyperchromatic nuclei
how are malignant neoplasms graded?
- Well differentiated - Grade 1
- Moderately differentiated - Grade 2
- Poorly differentiated - Grade 3
what is carcinomatosis?
when the patient has widespread metastases
what is an anaplastic tumour?
where the cell-type of origin of a malignant neoplasm is unknown/ cannot be identified
what is the structure of a neoplasm?
- Consists of neoplastic cells surrounded by a stroma
* Stroma provides mechanical and nutritional support to the neoplastic cells
why do malignant neoplasms contain a central necrosis?
outgrows blood supply (rate of growth is greater than rate of angiogenesis, so causes cells at centre of neoplasia to necrose)
what are the 2 types of benign epithelial neoplasm?
- Papilloma- benign tumour of non-glandular, non-secretory epithelium
- Adenoma- benign tumour of glandular/ secretory epithelium
what are the 2 types of malignant epithelial neoplasm?
- Carcinoma- malignant tumour of epithelial cells
- Adenocarcinoma- carcinomas of glandular epithelium
what is a lipoma?
benign tumour of lipocytes of adipose tissue
what is a rhabdomyosarcoma?
malignant tumour of striated muscle
what is a leiomyoma?
benign tumour of smooth muscle cells
what is an angiosarcoma?
malignant tumour of blood vessels
what malignant tumours do not follow the normal nomenclature?
- Melanoma (malignant neoplasm of melanocytes)
- Mesothelioma (malignant neoplasm of mesothelial cells)
- Lymphoma (malignant neoplasm of lymphoid cells)
what are teratomas?
- Neoplasm formed of all 3 germ cell layers- ectoderm, mesoderm, endoderm
- Tumour may contain teeth/ hair on appearance and then histologically contain various types of epithelium
what are blastomas?
tumours that resemble the embryonic form of the organ from which they arise
what are the problems with identifying carcinogens?
latent interval may be decades (may forget over time- i.e. forget what you were exposed to months/ years back), complexity of environment (lots of different chemicals present in each environment), ethical constraints
what is the process of metastasis?
- Detachment of tumour cells from their neighbours
- Invasion of surrounding extracellular matrix and connective tissue to reach conduits for metastasis (blood vessels and lymphatics)
- Intravasation into the lumen of vessels
- Evasion of host defence mechanisms- via aggregation with platelets, shedding of surface antigens and adhesion to other tumour cells
- Adherence to endothelium at a remote location
- Extravasation of cells from the vessel lumen into the surrounding tissue
- Growth at metastatic site
- Angiogenesis- angiogenesis promoters- vascular endothelial growth factor, basic fibroblast growth factor. Angiogenesis inhibitors- angiostatin, endostatin, vasculostatin
give some examples of screening programmes
cervical, breast and colorectal cancer
what are the 3 routes of metastasis?
haematogenous, transcoelomic, lymphatic
