8. Neoplasia 1 Flashcards
(56 cards)
Neoplasm
• An abnormal growth of cells that persists after the initial stimulus is removed
Malignant neoplasm:
- An abnormal growth of cells that persists after the initial stimulus is removed AND invades surrounding tissue with potential to spread to distant sites
- Spread – metastasis
Hyperplasia
• Is a growth in number of cells but this is a physiological condition, due to an increase in demand
Tumour:
• Any clinically detectable lump or swelling. A neoplasm is just one type of tumour.
Cancer:
• Any malignant neoplasm.
Metastasis:
• A malignant neoplasm that has spread from its original site to a new non-contiguous site. The original location is the primary site and the place to which it has spread is a secondary site.
Tumours can be
• Non neoplastic = not cancer e.g. dysplasia
• Neoplastic = cancer
○ Benign
○ Malignant
▪ Primary or secondary (metastatic that can spread)
Dysplasia
- A pre-neoplastic alteration in which cells show disordered tissue organisation. It is not neoplastic because the change is reversible.
- Associated with cancer but doesn’t have to lead to cancer
Benign neoplasms
• Benign tumours grow in a confined local area and so have a pushing outer margin. This is why they are so are rarely dangerous. They grow in one area and stay there. ○ Obstructions, can block things ○ Loss or gain of function ○ Pressure on things like nerves ○ Create stress or anxiety ○ Can become malignant
Malignant neoplasm
• Malignant tumours have an irregular outer margin and shape and may show areas of necrosis and ulceration (if on a surface). Tumour breaks into pieces and spreads (metastasis = death)
○ Block things like intestines
○ Use a lot of nutrients in cancer cells
○ Destroy organs by invading tissues
○ Bleeding – blood loss
Benign Neoplasms under the microscope
• Benign neoplasms have cells that closely resemble the parent tissue, i.e. they are well differentiated.
○ Look very similar to how they should look, still have fucntion
Malignant Neoplasms under the microscope
• Malignant neoplasms range from well to poorly differentiated. Cells with no resemblance to any tissue are called anaplastic.
○ Poor differentiation is bad as it doesn’t resemble normal tissue so tissue is completely abnoral
Things to look for in tumour cells
—> With progressing differentiation individual cells have increasing nuclear size and nuclear to cytoplasmic ratio, increased nucleus staining (hyperchromasia), more mitotic figures and increasing variation in size and shape of cells and nuclei, which is called pleomorphism.
Modified Bloom-Richardson Grading System
- Tubele formation – normally turns into a loss of tubele
- Nuclear polmorphism - loo at nuclear size
- Mitotic figures
Increase protein expression to increase proliferation and growth
The term grade is used to indicate differentiation, high grade being poorly differentiated Modified Bloom Richardson grading for breast cancer 1. Tubules 2. Mitoses 3. Nuclear pleomorphism G1, G2, G3 Higher grade = more severe cancer Survival of eprson depends on grade
Carcinoma in situ
• Carcinoma in situ = still limited by basement membrane and can’t invade tissue and dermis
Invasive carcinoma
• Invasive carcinoma = invade past basement membrane
Evolution of a squamous cell carcinoma
- Normal
- Dysplasia
- Carcinoma in situ – all cells have changed but basement membrane is still intact
- Invasion – erosion of basement membrane tumour accesses vascular channels
- Metastasi – can spread to different organs through blood or lymph
Stages in the development of a carcinoma
- Normal tissue
- Dysplasia and abnormalities
- Full blow cancer cells invading underneath tissues
Carcinoma
Malignant tumour of epithelial cells
Characteristics of benign tumour
• Sessile • Pedunculated • Paillary These 3 are normally on benign tumours – don't invade, limited • Exophilic growth grow outwards Surface in intact
Characteristics of malignant tumours
• Exophytic/ fungating • Ulcerated • Annular These 3 are normally malignant tumours • Invade tissue • Endophytic growth • Invade blood and lymph • Look like a crab • Necrosis inside
Cancer cells must
• Sustaining proliferative signalling ○ Signalling is important – cells won't proliferate without signals • Evading growth supressors ○ Avoid p53 • Ennabling replciative mortality ○ Find away to mainatin telomeres – telomerase • Introducing angiogenesis • Resisitng cell death ○ Resist apoptosis
Genetic Alterations:
- Mutations,
- deletions,
- amplifications,
- translocations,
- rearrangements
Epigenetic changes:
- DNA methylation,
* chromatin modifications
