Neoplasia III #7 (2/1/16) Flashcards Preview

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Flashcards in Neoplasia III #7 (2/1/16) Deck (25)
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1
Q

______ is the prototypic anti-apoptosis gene.

A

BCL2

2
Q

What does overexertion of BCL2 protein cause?

A

It protects cells form apoptosis, allowing them to survive for prolonged periods. Results in steady accumulation of cells often seen in low grade lymphomas.

3
Q

Tumors cannot grow larger than 1-2mm in diameter, unless ____________.

A

they are vascularized (nutrients and oxygen)

4
Q

What provides tumors access to vasculature?

A

Angiogenesis facilitated metastases

5
Q

T or F, only certain subclasses may be capable of metastasizing?

A

True

6
Q

What are the 2 major phases of Invasion and Metastasis?

A
  1. Invasion of the extracellular matrix

2. Vascular dissemination and adhesion/homing of tumor cells.

7
Q

What are steps of Invasion of the Extracellular matrix?

A
  1. Tumor cells detach from each other
  2. Attach to ECM components (BM and CT) inculding collagens, glycoproteins and proteoglycans.
  3. Degrade matrix components
  4. Migration
8
Q

Where are tumor cells vulnerable?

A

when in circulation

9
Q

Tumor metastasis is a function of _____ and _____.

A

Site and vascular/lymphatic drainage

10
Q

What are 3 conditions that involve unstable DNA?

A
  1. Hereditary nonpolyposis colon Ca Syndrome: mismatch repair defect, increase in MSI.
  2. Xeroderma pigmentosum: increase skin cancers, inability to repair UV damage.
  3. Bloom syndrome: ataxia telangiectasia, fanconi anemia, familial breast cancers, fragile DNA diseases.
11
Q

T or F, No single mutation results in cancer.

A

True, cancers usually exhibit multiple genetic alterations ..

12
Q

Overtime tumors can become more aggressive, why?

A

Probably due to acquisition of multiple mutations during tumor growth, resulting in numerous “subclones” with different characteristics such as drug resistance, resistance to hypoxia….Basically natural selection in a malignant lesion.

13
Q

What 3 types of Karyotypic changes in tumors?

A

Balanced translocations = extremely common, especially in hematopoietic neoplasms (often between chromosome 22 and 9)

Deletions = rentinoblastoma (Rb), colon and oral Ca.

Gene Amplifications = neuroblastoma and breast cancers.

14
Q

What are the 3 major factor that are associated with genetic damage?

A

Chemicals (carcinogens)
Radiant energy
Oncogenic viruses

15
Q

_____ chemicals require no chemical transformation to be carcinogenic.

A

Direct reacting

16
Q

Most chemicals are ______.

A

Indirect carcinogens = only become active after metabolic conversion, also called “Procarcinogens”

17
Q

What do chemical “promoters” do?

A

Enhance the actions of carcinogens, but have little inherent mutagenicity.

18
Q

What are some sources of Radiation carcinogenesis?

A
  • ultraviolet light
  • x-rays
  • radionucleotides
  • Gamma radiation from nuclear fission
19
Q

What are 2 types of Viral oncogenesis?

A
  1. RNA oncogenic viruses: Human T-ce;; leukeia Virus type 1

2. DNA oncogenic viruses: HPV and cervical Ca, EBV and burkitt lymphoma.

20
Q

What factor aid in tumor immunity?

A

Tumor Antigens = tumor specific antigens and tumor associated antigens .

Anti tumor Effector Mechanisms = Cytotoxic T cells (CD8+). natural killer cells, Macrophages, humoral factors.

Immunosurveillance = Strongest argument is increased frequency of cancer observed in immunocompromised.

21
Q

How can a tumor “evade” the immune system?

A
  • Selection of antigen negative variants
  • Reduced expression of HLA antigens
  • Lack of T cell co-stimulation - sensitization requires 2nd signal together with foreign antigen
  • Immunosuppression
22
Q

What are the 5 clinical features of Neoplasia?

A
  1. Location - adjacent to vital stuructures?
  2. Functional activity - hormone synthesis
  3. Ulceration - bleeding secondary infection
  4. Cachexia - progressive wasting state
  5. Paraneoplastic syndromes (10-15% of Ca pts): Hypercalcemia, Cushing’s syndrome, paraneoplastic pemphigus.
23
Q

What is Grading?

A

Refers to an estimate of the aggressiveness of a cancer based microscopic appearance.

24
Q

What is staging?

A

Describes cancer extent: size of primary lesion, lymph node involvement, and metastatic spread as estimated by clinical exam and imaging.

25
Q

How do labs diagnose cancer?

A
  • biopsy
  • electron microscopy
  • frozen section biopsy
  • fine needle aspiration biopsy
  • cytologic (Pap smear)
  • Flow cytometry