Week 4: Neoplasia Flashcards
Atrophy
Decrease in the size and function of a cell
Causes:
- Decreased workload
- Decreased blood supply
- Loss of innervation
- Interruption of trophic signals
- Aging
Cells may die.
Hypertrophy
Increase cell size (function is altered)
Causes:
- Increased functional demand
- Hormones
Hyperplasia
Increase in cell number in organ or tissue
Causes:
- Increased functional demand
- Hormones
- Persistent cell injury (calluses)
Metaplasia
Conversion of one differentiated cell to another
Protective mechanism, but may have loss of function
Dysplasia
Alterations in shape, size, and organization of cell components
- Enlargement
- Irregular
- Hyperchromatism of nuclei (dark)
DYSPLASIA IS PREMALIGNANT/PRECANCEROUS - curable if identified.
Cause: persistent injury
Pleomorphism
Variation in shape and size (nuclear or cellular). Seen in Dysplasia
Neoplasm
Abnormal mass of tissue (tumour). Growth is uncoordinated and massive.
Even if you take away stimuli, it will continue to grow
Named according to the type of tumour cells (indicating the tissue of origin) and the nature of the tumour whether benign or malignant
Cancer
Malignant neoplasm
Oncology
Study of tumours
Benign Tumours
Tissue type + oma
Adenoma: benign tumour that forms a gland or came from glands
Cystadenoma: An adenoma with cystic areas
Papilloma: Benign tumours with finger-like projections.
Polyp: Elevated mucosal lesions (descriptive term).
Exceptions: melanoma/lymphoma are both malignant
All cats poop purple
Malignant Tumours
Sarcoma: composed of mesenchymal cells (fat, bone, muscle)
Fibrosarcoma: fibrous tissue
Carcinoma: composed of epithelial cells
Adenocarcinoma: malignant epithelial tumor forming a glandular pattern
Squamous cell carcinoma: squamous cells
Teratoma
2 or more germ layers from mesenchymal cells
Benign OR malignant
Choristoma
Ectopic rest (when tissues move during development and stay there)
Looks like a tumour but is not
Hamartoma
Disorganized normal tissue in normal location
Cyst
Fluid filled space
Differentiation
How much tumour cells looks like their normal counterparts (morphologically and functionally)
Well –> moderate –> poor
Well = looks like their normal counterpart Poor = looks very abnormal (also less functionally active)
Anaplasia
Loss of specialized features of a normal cell
Lacks differentiation (looks very abnormal)
used ONLY for INVASIVE NEOPLASM
Features of Anaplastic Cells
- Variable cell size & shape (cellular pleomorphism).
- Variable nuclear size & shape (nuclear pleomorphism).
- Increased nuclear cytoplasmic ratio
- Hyperchromatic nuclei (Inc. DNA)
- Increased mitosis and atypical mitosis.
- Loss of polarity
- Tumour giant cell
Rate of Growth
Benign tumours - slow growing (unless hormonal stimulation)
Malignant tumours - fast growing
FAST rate of growth = INC. blood supply
FAST rate of growth = less differentiation
Invasion
Reliable feature of malignancy
Benign tumours DO NOT INVADE - grow by expansion (locally)
Malignant tumours invade and destroy tissue
- most carcinomas have monoclonal origin
- if basement membrane is intact, they are carcinoma in situ (severe dysplasia), carcinoma is the final stage
Metastasis
Tumour that disconnected from primary tumour.
UNEQUIVOCAL sign of malignancy (NEVER seen in benign tumours) - it will look like the tumour from the origin site.
Pathway:
- Seeding via body cavities (peritoneal)
- Lymphatic spread: most common; follows natural drainage
- Hematogenous spread (blood vessels): favoured by sarcoma but also used by carcinoma. Lung and liver, other tissues. Follows routes of venous drainage
Transformation
Most tumours are derived from a single transformed cell. Not subject to normal growth/differentiation control.
- Self sufficiency in growth signal (autonomous)
- Insensitivity to growth-inhibitory signal
- Resistant to apoptosis
- Defective DNA repair
- Unrestricted proliferation
- Angiogenesis, invasion and metastasis
Tumour Growth
Excess cell production = rapid growth
Growth fraction = #cycling cells / # total cells
Doubling time is similar/more than normal cells.
Minimum size for clinical detection: 1cm3 (1gm) = 108-109 cells
If more proliferative = chemotherapy
Tumour Angiogenesis (munchy time)
Blood supply is a major factor for growth.
Angiogenic (food):
- produced by tumour cells
- produced by inflammatory cells infiltrating tumours
Induces production of proteolytic enzymes (VEGF)
Tumour Progression and Heterogeneity
Over time, tumours develop subpopulations that vary in invasiveness, metastatic potential, growth factor requirement, antigenicity
Subpopulation “beat the odds and survive
Warburg Metabolism
Cancer cell metabolism
Prefer glycolysis over oxphos
Some oncoproteins causes formation of abnormal metabolite causing epigenetic changes