Neoplasia Flashcards

1
Q

What is the mechanism for an INITIATOR carcinogen? What is an example?

A

Directly cause DNA damage, usually an electrophilic molecule that strips electrons from DNA and promotes strand cross-linkage e.g nitroasmines

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2
Q

What is the mechanism for a PROMOTER carcinogen? What is an example?

A

Supports the proliferation of mutated cells such that larger numbers of mutated progeny have better chance of becoming neoplastic e,g oestrogen, progesterones, other hormones

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3
Q

What is the mechanism for a COMPLETE carcinogen? what is an example?

A

Can both initiate DNA damage and encourage growth and proliferation of mutated cells e.g spanish fly, ionising radiation

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4
Q

Why are children and young animals more sensitive to neoplasia from ionising radiation?

A

Because they have a larger proportion of regularly-dividing cells, as they are growing. The carcinogenic effect of ionising radiation is particularly potent in rapidly dividing cells.

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5
Q

What are some types of ionising radiation?

A

Xrays, particulate radiation (protons, neutrons, alpha particles)

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6
Q

Causing which cancer types in ANIMALS has UV radiation been implicated?

A

Cutaneous and conjunctival SCC, dermal haemangiosarcomas in dogs and cats. Especially non-pigmented areas. Not technically ionising but can induce ROS production which is the mechanism for DNA damage

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7
Q

Name three microbiological carcinogens and whether they are direct or indirect carcinogens

A
  1. feline leukaemia virus promotes oncogene expression so DIRECT
  2. hepatitis virus causes prolonged inflammation in the liver that can lead to oncogenesis INDIRECT
  3. papillomavirus inhibits p53 DIRECT
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8
Q

Benign neoplasm of glandular epithelial tissue

A

Adenoma

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9
Q

Malignant neoplasm of glandular epithelial tissue

A

Adenocarcinoma

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10
Q

Benign neoplasm of non-glandular epithelial tissue

A

Papilloma

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11
Q

Malignant neoplasm of non-glandular epithelial tissue

A

Carcinoma

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12
Q

Benign neoplasm of mesenchymal tissue

A

-oma

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13
Q

Malignant neoplasm of mesenchymal tissue

A

sarcoma

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14
Q

Benign/malignant neoplasm of sebaceous gland

A

Sebaceous adenoma, sebaceous adenocarcinoma

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15
Q

Benign/malignant neoplasm of cartilage

A

Chondroma/chondrosarcoma

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16
Q

Benign/malignant neoplasm of squamous epithelium

A

Squamous papilloma/squamous cell carcinoma

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17
Q

Benign/malignant neoplasm of prostate

A

Prostatic adenoma, prostatic adenocarcinoma

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18
Q

Benign/malignant neoplasm of endothelial cells

A

Haemangioma/haemangiosarcoma

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19
Q

Benign/malignant neoplasm of thyroid

A

Thyroid adenoma, thyroid carcinoma

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20
Q

Benign/malignant neoplasm of fibrocytes

A

Fibroma, fibrosarcoma

21
Q

Benign/malignant neoplasm of skeletal muscle

A

Rhabdomyoma, rhabdomyosarcoma

22
Q

Benign/malignant neoplasm of urothelial cells

A

Urothelial papilloma, urothelial carcinoma

23
Q

Malignant neoplasm of plasma cells

A

plasmacytoma

24
Q

Benign/malignant neoplasm of macrophages

A

Histiocytoma, histiocytic sarcoma

25
Q

Benign/malignant neoplasm of melanocytes

A

Melanocytoma, melanoma

26
Q

Define neoplasia

A

Unregulated growth of cells derived from normal tissue caused by irreversible genetic change. May be benign or malignant

27
Q

What is tumour stroma usually composed of?

A

Fibrous CT, blood vessels, inflammatory cells

28
Q

List the features that differentiate malignant neoplasms from benign. Which of these are the only DEFINITIVE features?

A
  1. Invasion /infiltration of adjacent tissue *
  2. Metastasis to distant sites *
  3. Degree of cell differentiation
  4. Increased growth rate
29
Q

What creates the capsule of a benign neoplasm?

A

The surrounding host cells atrophy under the pressure of the expanding mass. They are replaced with fibrous tissue, creating the capsule

30
Q

What are the three pathways for metastasis? Which neoplasms are most likely to use each one?

A
  1. Haematogenous - typical of sarcomas
  2. Lymphatic - typical of carcinomas
  3. Implantation
31
Q

What does anisocytosis mean?

A

Variation in cell size

32
Q

What does anisokaryosis mean?

A

Variation in nuclear size

33
Q

What does anisonucleosis mean?

A

Variation in nucleolar size

34
Q

Which features of pleiomorphism are more convincing of malignancy?

A

Those that affect the deepest cellular structures e.g anisonucleosis

35
Q

Other than pleiomorphism, what are 6 histological features of neoplastic cells?

A
Increased nuclear to cytoplasmic ratio 
Hyperchromatic nuclei
Giant cells with multiple nuclei
Loss of polarity 
Failure to form normal structures 
Atypical mitoses
36
Q

Define choristoma

A

Normal cells in an abnormal location

37
Q

Define harmatoma

A

Normal cells in their normal location forming an abnormal mass

38
Q

List three local effects of neoplasia

A
  1. Compression/distortion of local structures
  2. Impediment of movement
  3. Ulceration, infection
39
Q

List three systemic effects of neoplasia

A
  1. Pyrexia
  2. Cancer cachexia
  3. Secretion of abnormal hormones or autoimmune disease (paraneoplastic syndrome)
40
Q

List three mechanisms by which TNFalpha secretion causes cancer cachexia

A
  1. Appetite suppresion
  2. Increased protein catabolism
  3. Stimulation of lipolysis
41
Q

What is pseudohyperparathyroidism of malignancy? With which tumour types does it tend to be associated?

A

Tumour secreting Parathyroid Hormone related Protein which is causing Ca2+ extrusion from peripheral tissues and hypercalcemia
May get bone resorption, osteoporosis
Commonly due to lymphoma or anal gland carcinoma

42
Q

What are two autoimmune conditions that may be caused by anti-tumour antibodies cross reacting with self antigen?

A
  1. Myasthenia gravis

2. Immune mediated haemolytic anemia

43
Q

How do proto-oncogenes contribute to neoplasia and what are two examples

A

Upregulation of protooncogenes results in excessive stimulus for cell growth and proliferation e.g Ras, cyclin D1
Are one-hit (dominant)

44
Q

How do tumour suppressor genes contribute to neoplasia and what are two examples

A
Downregulation of tumour suppressor genes results in cell being allowed to divide despite having sustained genetic damage e.g retinoblastoma  (Go > G1) and p53 (detects DNA damage, induces apoptosis)
Two hit (recessive)
45
Q

How do DNA repair genes contribute to neoplasia?

A

Deactivation of these means cell with DNA damage cannot repair it. May proceed to cell cycle and pass along its damaged DNA, allowing mutations to accumulate

46
Q

What are the four kinds of gene that are involved in oncogenesis?

A
  1. Proto oncogenes
  2. Tumour suppressor genes
  3. DNA repair genes
  4. Apoptosis regulating genes
47
Q

List the 8 hallmarks of neoplasia LAASSIEE

A
  1. Limitless proliferation > telomerase
  2. Altered cellular metabolism >glycolysis
  3. Ability to invade and metastasise * malignant only
  4. Sustained angiogenesis > VEGF, hypoxia
  5. Self sufficiency in growth signalling > Ras
  6. Insensitivity to growth inhibitory signals > P53
  7. Evasion of immune system > suppress MHC I
  8. Evasion of apoptosis > BCL-2

LAASSIEE

48
Q

Describe the metastatic cascade

A
  1. Local invasion
  2. Intravasation into blood and lymph
  3. Transit through vasculature
  4. Extravasation
  5. Formation of micro-metastases
  6. Growth of micro-metastases into macroscopic tumours
49
Q

List some adaptations tumour cells must have to metastasise

A
  1. Loosening of cell-cell contact
  2. Expression of matrix metalloproteinases
  3. Cell motility
  4. Ability to survive in blood/lymphatics
  5. Expression of adhesion factors at metastasis site