Neoplasia Flashcards
What are four types of cell growth?
1) hypertrophy- cell increases in size
2) hyperplasia- increase in number
3) metaplasia- transformation of one cell type into another
4) dysplasia- abnormal pattern of tissue growth
What is neoplasia?
When cells have undergone genetic changes to allow them to be unresponsive to their normal growth controls and expand beyond their normal anatomic boundaries.
What are the characteristics of a benign neoplasia?
1) well differentiated 2) uniform size and shape 3) normal nuclear morphology 4) few mitoses 5) encapsulated and expansive 6) no metastases
What are the characteristics of a malignant neoplasia?
1) poorly differentiated and anaplastic 2) pleomorphic- variable size and shape 3) abnormal nuclear morphology 4) increased and bizarre mitoses 5) non-encapsulated and infiltrative 6) metastasises
What is metastasis?
Neoplasms that are discontinuous with the original tumour.
How would you name a benign epithelial neoplasm?
A papilloma (surface epithelium) or an adenoma (glandular epithelium)
How would you name a malignant epithelial neoplasm?
carcinoma- surface ep.
adenocarcinoma- glandular ep
How would you name mesenchymal neoplasms?
Benign- fibroma, lipoma (-oma)
Malignant- fibrosarcoma, liposarcoma (-sarcoma)
What are some examples of round neoplasms?
Involving the cells of the blood e.g. lymphosarcoma, mast cell tumour, plasmacytoma, leukaemia.
Examples of other neoplasms?
melanoma ( not benign), meningioma
and embryological one is -blastoma
What are the three causes of neoplasia at a genetic level?
Single inherited mutated gene
Multiple inherited genes
Acquired somatic mutations
What is an example of single inherited mutated gene?
NF-1, NF-2 genes that cause neurofibroma.
What are the two causes of acquired somatic mutations?
1) intrinsic factors- Reactive oxygen species or DNA polymerase errors (cant prevent these)
2) extrinsic factors e.g. chemical, radiation, viruses, bracken fern, aflatoxin in fungi.
What are the 4 molecular determinants of neoplasia?
1) growth promoting oncogenes e.g. Ras
2) growth inhibiting tumour suppressor genes e.g. p53, RB, APC, Beta-catenin and E-cadherin
3) Apoptosis genes e.g. p53
4) DNA repair genes e.g. BRCA 1 and 2
What does Ras do?
It promotes growth and division so if it is mutated it promotes excessive transcription of growth factors.
What do p53 and RB do?
The guardians of the genome- They are both pro apoptotic genes. p53 decides what to do at G2/M. RB decides what to do at G1/S, it prevents excessive replication.
What is the significance of a mutation in the APC WNT-Beta-catenin pathway?
If the APC gene is mutated then it will constantly allow B-catenin into the cells to promote transcription. Often the mutation is also linked to E-cadherin which is what holds the cells to each other, if this is damaged the mutated cell can grow beyond its own boundaries and even move.
Why is angiogenesis important for the neoplastic cell?
Neoplasms cannot grow more than 1-2mm diameter without their own blood supply. They alter the balance between pro-angiogenic and anti-angiogenic substances to promote blood vessel growth.
Where can a neoplastic cell get its blood supply from?
It can recruit from bone marrow cells and make its own new blood vessel or it will cause vessels to sprout from existing ones.
What are the three different routes of metastasis?
1) Haematogenous spread- via the blood e.g. scarcoma. They will enter the veins and go to the lung/liver.
2) Lymphatic e.g. carcinoma
3) Transcoelomic- seed into body cavities e.g. ovarian adenocarcinomas
What is crucial for a neoplastic cell to successfully metastasise?
It needs to have the metastatic signature- it needs to express or suppress genes that are specifically involved in metastasis. This can be used to predict the metastatic potential of a tumour.
What immune cells are involved to fight neoplastic cells?
CD8+ T cells, MHC, NK cells and macrophages