Neoplasia Flashcards

1
Q

What is neoplasia?

A

-new growth that is NOT under the normal control mechanisms

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2
Q

What is desmoplasia?

A

=fibrous stroma present in some cancers

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3
Q

What are the two basic components of all tumors (benign or malignant)?

A
  1. Neoplastic cells that constitute the tumor parenchyma
  2. Reactive stroma made up of connective tissue, blood vessels, and variable numbers of cells of the adaptive and innate immune system
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4
Q

What makes a tumor benign?

A
  • gross and microscopic appearances are considered relatively innocent, implying that it will remain localized,
  • will not spread to other sites
  • is amenable to local surgical removal
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5
Q

What are the general rules for naming a benign tumor?

A

“root word” + _oma

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6
Q

What is a polyp?

A
  • a tumor that projects into a lumen, usually GI tract

- usually benign

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7
Q

A rhabdomyoma is a:

A. Malignant tumor of smooth muscle
B. Benign tumor of fat
C. Benign tumor of skeletal muscle
D. Malignant tumor of collagen

A

C. Benign tumor of skeletal muscle

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8
Q

What are the general rules for naming a malignant tumor?

A

-“Root word” + carcinoma or sarcoma

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9
Q

What is a mixed tumor?

A
  • a divergent differentiation of a single neoplastic clone in a tumor
  • contain epithelial components scattered within a myxoid stroma that my contain cartilage or bone
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10
Q

What is a Hamartoma?

A
  • A disorganized by benign-appearing masses composed of cells indigenous to the particular site
    e. g. A pulmonary chondroid hamartoma contains islands of disorganized but histologically normal cartilage, bronchi, and vessels
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11
Q

What is a Choristoma?

A
  • A heterotopic rest of cells
  • developmental, not a metastasis
    e. g. A small nodule of well-developed and normally organized pancreatic substance may be found in the submucosa of the stomach, duodenum, or small intestine
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12
Q

What are the common exceptions to the benign vs cancer naming conventions?

A

Lymphoma – malignant tumor of lymphoid cells

Hepatoma – malignant liver tumor

Neuroblastoma – malignant tumor of primitive neural tissue

Wilms tumor – malignant renal tumor

Ewing sarcoma – malignant bone tumor

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13
Q

What does differentiaton mean in context of tumors?

A

How closely the tumor resembles normal tissue

**we do not talk about differentiation in benign tumors

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14
Q

What is anaplasia?

A
  • lack of differentiation in tumors

- so poorly differentiated, we can’t tell what organ it came from

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15
Q

What are the histological characteristics of malignant anaplasia?

A

Pleomorphism

Hyperchromasia

High nuclear:cytoplasmic (N:C) ratio

Prominent nucleoli

High mitotic rate, abnormal mitotic figures

Tumor giant cells

Loss of normal orientation

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16
Q

What is pleomorphism ?

A
  • variability in size and shape
  • range from small to tumor giant cells (variability in size)

**not to be confused with normal giant cells

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17
Q

What is hyperchromatism?

A

-A lot of DNA chromatin (very dark)

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18
Q

What is a papilloma?

A

-benign tumor with “finger-like” projections on a surface into a lumen

**don’t confuse with polyp, it is a subclass of polyps

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19
Q

What does Sarcoma mean?

A

-the tumor is derived from mesenchymal tissues

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20
Q

What does carcinoma mean?

A

-the tumor is derived from epithelial tissue

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21
Q

What is dysplasia? Is it reversible?

A
  • loss of uniformity of cells, loss of normal architecture
  • Usually applied to epithelial surfaces
  • dysplasia is reversible, but may be a precursor to malignant transformation
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22
Q

What does Carcinoma in Situ mean?

A

-dysplastic features involving the whole thickness of the epithelium, but no invasion into deeper tissue

**not actually a carcinoma, malignancy occurs when it invades past the basement membrane

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23
Q

Why do benign tumors usually develop a rim of compressed fibrous tissue called a capsule?

A

-benign tumors grow and expand slowly

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24
Q

________ unequivocally marks a tumor as malignant.

A

-metastasis

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25
Q

What increases the likelyhood that a tumor is metastasizing?

A
  • lack of differentiation
  • aggressive local invasion
  • rapid growth
  • Large size
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26
Q

What is hematogenous spread of a cancer?

A
  • metastasis via the blood vasculature

* more common in Sarcomas

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27
Q

Is dysplasia reversible?

A

Yes

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28
Q

What is the most common abnormality of protooncogenes in human tumors?

A
  • point mutation in the RAS family of genes

* 15-20% of all human malignancies contain mutated versions

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29
Q

What does the activated RAS protein do?

A
  • RAS is a protooncogene
  • a member of a family of small G proteins that bind guanosine nucleotides
  • Stimulates downstream regulators of proliferation, in favor of proliferation
  • efforts to find an inhibitor of this protein are difficult due to vague structure and pathways
30
Q

What do BRAF and PI3K do?

A
  • Protooncogenes
  • BRAF and PI3K are serine/threonine protein kinases
  • Mutation in these genes Remove inhibition of apoptosis
31
Q

What is the cause of Chronic Myelogenous Leukemia? How is it treated?

A
  • ABL gene translocated from chromosome 9 to 22, where it fuses with BCR gene
  • codes for rogue tyrosine kinase

**Treated with imatinib mesylate, inhibits the rogue kinase

32
Q

How is the MYC oncogene involved in carcinogenesis?

A
  • it activates genes that are involved in proliferation & is expressed in virtually all eukaryotic cells
  • in some contexts, MYC upregulates expression of telomerase

**MYC is one of a handful of transcription factors that can act together to reprogram somatic cells into pluripotent stem cells

33
Q

The orderly progression of cells through various phases of cell cycle is orchestrated by _________________.

A

cyclin-dependent kinases (CDKs)

34
Q

What are some examples of tumor suppressor genes (TSGs)?

A
  • Rb (retinoblastoma)
  • p53
  • BRCA 1 & 2
  • APC
  • NF1/2, TGF-beta, WT-1, PTEN, VHL
35
Q

What does activated and inactivated Rb do? Which point in the cell cycle does it control?

A
  • Inactivated: Allows transcription
  • Activated: Cycle halts
  • stops at the G1->S check point
36
Q

What are the two ways in which Rb can be compromised?

A
  • Loss-of-function mutations involving both RB alleles
  • A shift from the active hypophosphorylated state to the inactive hyperphosphorylated state by gain-of-function mutations that upregulate CDK/cyclin D activity or by loss-of-function mutations that abrogate the activity of CDK inhibitors
37
Q

What does p53 normally do?

A
  • tumor suppressor gene
  • regulates cell cycle progression, DNA repair, cellular senescence, and apoptosis
  • serves as the focal point of a large network of signals that sense cellular stress

**is the most frequently mutated gene in human cancers

38
Q

What is Li-Fraumeni syndrome?

A

-inheritance of a mutated copy of p53, which predisposes individuals to malignancies (one copy is already out of the picture)

=25x greater chance to develop cancer

-cancer often developed at a young age

39
Q

How does p53 fight neoplastic transformation (3 ways)?

A
  • Activation of temporary cycle arrest (quiescence)
  • Induction of permanent cell cycle arrest (senescence)
  • Triggering of programmed cell death (apoptosis)
40
Q

How does the MDM2 protein affect p53?

A
  • it stimulates the degradation of p53

* MDM2 gene is amplified in 1/3 of sarcomas

41
Q

How does HPV cause cancer?

A
  • binds p53 and promotes its degradation

* Also occurs in several DNA viruses

42
Q

How does a tumor’s p53 status affect cancer treatment techniques?

A
  • Irradiation and conventional chemotherapy mediate their effects by inducing DNA damage and apoptosis
  • Tumors with normal p53 alleles are more likely to be killed by such therapy than tumors with mutated p53
43
Q

What are Adenomatous polyposis coli genes (APC)?

A

Adenomatous polyposis coli genes (APC) are a class of tumor suppressors whose main function is to down-regulate growth promoting signals

**mutations common in colorectal carcinomas, as well as liver cancer

44
Q

What disease is associated with germ-line APC mutations?

A
  • Familial adenomatous polyposis

- pt develops thousands of polyps in teens and 20’s

45
Q

What are the four classes of normal growth regulatory genes?

A
  1. Growth promoting proto-oncogenes
  2. Growth inhibiting tumor suppressor genes
  3. Genes that regulate Apoptosis
  4. Genes involved in DNA repair
46
Q

What are driver mutations?

A

-mutations that contribute to the development of the malignant phenotype

47
Q

Aberrant DNA methylation is responsible for __________.

A

The silencing of tumor suppressor genes

48
Q

What are the eight key changes in the molecular basis of malignancy?

A
  1. Self sufficiency in growth signals
  2. insensitivity to growth-inhibitory signals
  3. Evasion of apoptosis
  4. Limitless replicative potential
  5. Sustained Angiogenesis
  6. Ability to invade or metastasize
  7. Defects in DNA repair
  8. Altered Cellular metabolism
49
Q

What are oncogenes?

A

-genes that promote autonomous cell growth in cancer cells

**unmutated cellular counterparts are called proto-oncogenes

50
Q

What cancers are associated with exposure to arsenic?

A
  • lung carcinoma

- skin carcinoma

51
Q

What cancers are associated with exposure to Asbestos

A
  • Lung, esophageal, gastric, and colon carcinoma

- Mesothelioma (malignancy of the pleural surfaces)

52
Q

What cancers are associated with exposure to benzene?

A

Acute Myeloid Leukemia

53
Q

What cancers are associated with exposure to Beryllium?

A

-Lung Carcinoma

54
Q

What cancers are associated with exposure to Cadmium?

A

-Prostate Carcinoma

55
Q

What cancers are associated with exposure to Chromium compounds?

A

-Lung carcinoma

56
Q

What cancers are associated with exposure to Nickel Compounds?

A

-Lung & oropharyngeal carcinoma

57
Q

What cancers are associated with exposure to Radon?

A

-Lung Carcinoma

58
Q

What cancers are associated with exposure to Vinyl Chloride?

A

-Hepatic Angiosarcoma

59
Q

What are passenger mutations?

A

Mutations that lead to genomic instability greatly increase the frequency of mutations

60
Q

Tumors that recur after therapy almost always have _______ genotype than the original tumor

A

a different

61
Q

What are Protooncogenes?

A
  • genes that promote normal cell growth and development

- Over expression of these genes can lead to neoplasia

62
Q

What is the JAK-STAT mutation?

A
  • Associated with several myeloproliferative disorders
  • Point mutation in JAK2
  • This aberration activates transcription factors of the STAT family which promote the growth factor-independent proliferation and survival of tumor cells
63
Q

Dysregulation of ____ occurs in Burkitt Lymphoma.

A

MYC

64
Q

Why is it important that MYC can upregulate the expression of Telomerase?

A

Telomerase is one of several factors that contribute to the endless replicative capacity

**MYC is one of a handful of transcription factors that can act together to reprogram somatic cells into pluripotent stem cells

65
Q

What growth factors are involved in tumor angiogenesis?

A
  • VEGF

- bFGF

66
Q

Even if a solid tumor possesses all of the genetic aberrations that are required for malignant transformation, it cannot enlarge beyond 1 to 2 mm in diameter unless it has the capacity to induce ____________.

A

Angiogenesis

67
Q

What is the dual effect of angiogenesis on tumor growth?

A
  • Provides nutrients and oxygen

- newly formed endothelial cells stimulate the growth of adjacent tumor cells by secreting growth factors

68
Q

Why are lung and colorectal cancers frequently resistant to radiation and chemotherapy?

A

Lung and colorectal cancers frequently carry mutated p53 copies

69
Q

What does the grading of a tumor represent?

A
  • the degree of differentiation
  • Well, moderately, or poorly differentiated

=Histologic

70
Q

What does the staging of a tumor represent?

A

=anatomic

-Size of tumor and extent of spread

(I = localized, IV = extranodal mets)