Class 6 - Alterations in Cellular Proliferation, Neoplasia Flashcards
Cellular Adaptation
Can occur in response to both normal physiological and pathological conditions in the cells as they attempt to survive and maintain their function
Atrophy
- Same number of cells decrease in size
- Caused by a lack o workload/disuse
- Biceps, immobility causes disuse of muscle cells
- Alzheimer’s, disuse of cerebral cortex
- Atrophy of many cells can lead to tissue and organ atrophy
Hypertrophy
- Same number of cells increased in size
- Caused by increased workload (use)
Cardiac Hypertrophy
- In response to increased workload such as: hypertension, chronic high blood pressure, increased stress of pumping through diseased vessels (atherosclerosis)
Hyperplasia
- Increase in number of cells
- Response to injury when severe and prolonged, allows regeneration of tissue
- Often occurs with hypertrophy
Prostatic Hyperplasia
- Typically happens with age rather than stressor
- More common in men >50
- More cells = bigger organ/gland
- Could cause obstruction of the urethra
Metaplasia
- Replacement of one mature cell by another mature cell. Usually a simpler form
- Eg. Epithelial cells replaced by another type of mature, organized epithelial cells (reversible)
- Bronchi cells and smoking (reversible if smoking stops)
Dysplasia
- Abnormal change in size, shape, organization and of cells; the replacement of mature cells with less mature cels
- A precursor to malignancyy
- Not truly an adaptation
- Cells are immature and disorganized; can replace/reproduce quickly
- ## Reversible
Neoplasia
New growth, benign or malignant tumour
Prefix will indicate source tissue (lip, adeno)
Benign Tumour
- Suffix is oma, but not all oma are benign
- Cell well differentiated
- Encapsulated
- Cells grow slowly
- Not invasive
- Does not metastasize
Malignant Tumour
- Suffixes are sarcoma and carcinoma
- Poorly differentiated cells (general cells)
- Non-encapsulated
- Grows rapidly
- Generalized effects
- Invasive: sends out crab-like extensions
- Metastasis - can spread distantly
Characteristics of Cancer Cells
Autonomy
- Develop independence from normal cells, do their own thing, grow without stopping, ignore signals that say stop or die
Anaplasia
- Lack of differentiation, very simple cells that reproduce quickly
- Immature cells usually become mature cells with specific functions. In cancer, anaplasia describes how much or how little the tumour tissue looks like the normal tissue it came from.
- Well-differentaited cancer cells look more like normal cells and tend to grow and spread more slowly than poorly differentiated cells
Oncogenisis
Sustained growth:
- Anaplasia: non specific, grows very fast, not differentiated, not mature
- Sustained proliferation
- Evades growth suppressors
Resists death
- Avoid immune destruction
- Apoptosis dysregulated
- Replicative immortality
Invasion and metastasis
- Absent contact inhibition (when normal cells stop growing when they touch a neighbour)
- Less adhesion
- No anchorage dependence
- Motility
Promotes inflammation
- Cancer promotes inflammation, and chronic inflammation promotes cancer.
- More cell repair = more chances for cell mutuations
Inducing angiogenisis
- Creates own blood supply
Alternative fuel sources
- Lactic acid
- Pyruvate
- Anabolic byproducts can be used for fuel
Genetic instability
- Gross chromosomal abnormalities
- Aneuploidy, frame shift mutation
Classification and Staging of Tumors
Carcinoma in Situ
- Occurs after dysplasia
- Pre invasive
- Has not broken through the basement membrane or invaded the surrounding supporting tissue
Invasive
- Staging using TNM
- The higher the number T, the bigger the tumor
- The higher the number N, the more nodes (lymph nodes
- The higher the number M, the worse the metastasis
Stages 0-IV
- 0 is carcinoma in situ
- IV is metastasis
Normal - Dysplasia - In situ neoplasm - Invasive neoplasm
Risk Factors for Cancer
Modifiable
- Tobacco
- Alcohol
- Inflammation
- Infection (H. pylori, herpes, HPV, hepatitis)
- Occupation
- Ionizing radiation
- Number of menstrual cycels
- Number of sexual parterns
- UV
- Lack of physical activity (increases obesity, inflammatory mediators and free radicals, insulin and insulin-like growth factors, decreases gut motility)
Non Modifiable
- Age
- Genetics (down syndrome or breast cancer for women)
- Gender (hormones)
Early onset of menstruation, late menopause and a few/zero pregnancies have a lower risk of getting cancer.
Manifestations of Cancer
Fatigue
- Number 1 manifestation
- Subjective
- Caused by tumour mediators, biology, psychological aspects effects sleep
Pain
- Little or no pain is associated with early staged of malignancy - usually comes later
- Mechanisms: pressure, obstruction, invasion of sensitive structures, stretching of visceral surfaces, tissue destruction and inflammation
- Influenced by fear, anxiety , sleep, loss and fatigue
Hematologic: anemia
- Decreased hemoglobin in the blood
- Mechanisms: tumour invasion into the bone marrow, chronic bleeding, severe malnutrition, chemo therapy
Hematologic: luekopenia
- Decrease in WBC
Hematologic: thrombocytopenia
- Decrease in thrombocytes, increased risk for bleeding
Cachexia
- Most severe from of malnutrition
- Complex breakdown of our own tissue
- 80% of cancer patients at death
- Common with most solid tumors
- Most common in children and elderly
- Symptoms include: anorexia, early satiety, weight loss, anemia, taste alterations, altered protein/lipid/carbohydrate metabolism
Paraneoplastic Syndromes
Malignant tumour may secrete various substances that cause
- ADH secretion
- ACTH production
- Hypercalcemia
- Pro-coagulation factors
Esthesioneurobalstoma
- Rare cancer of the nasal vault
Treatment of Cancer
Goals
- Eradicate cancer cells while leaving as many normal cells as possible
- Cure
- Control tumour growth
- Decrease symptoms
Surgery
- Remove tumours
- Debulking surgery, remove most of mass
- Biopsy and lymph node sampling (sentinel nodes are the nodes closest to the tumour)
- Palliative surgery: prevents death from bowel obstruction
Others
- Ionizing radiation (local)
- Chemotherapy (systemic)
- Immunotherapy (vaccines, being trialed)
Side Effects of treatment
- Hair and skin loss
- bone marrow suppression
- Sloughing of the inner lining of Gi tract, bleeding, anorexia, diarrhea
- Reproductive tract, early menopause or infertility
