Neoplasia III #7 (2/1/16)

Question 1

______ is the prototypic anti-apoptosis gene.

Answer 1

BCL2

Question 2

What does overexertion of BCL2 protein cause?

Answer 2

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

Question 3

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

Answer 3

they are vascularized (nutrients and oxygen)

Question 4

What provides tumors access to vasculature?

Answer 4

Angiogenesis facilitated metastases

Question 5

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

Answer 5

True

Question 6

What are the 2 major phases of Invasion and Metastasis?

Answer 6

1. Invasion of the extracellular matrix

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

Question 7

What are steps of Invasion of the Extracellular matrix?

Answer 7

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

Question 8

Where are tumor cells vulnerable?

Answer 8

when in circulation

Question 9

Tumor metastasis is a function of _____ and _____.

Answer 9

Site and vascular/lymphatic drainage

Question 10

What are 3 conditions that involve unstable DNA?

Answer 10

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.

Question 11

T or F, No single mutation results in cancer.

Answer 11

True, cancers usually exhibit multiple genetic alterations ..

Question 12

Overtime tumors can become more aggressive, why?

Answer 12

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.

Question 13

What 3 types of Karyotypic changes in tumors?

Answer 13

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.

Question 14

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

Answer 14

Chemicals (carcinogens)
Radiant energy
Oncogenic viruses

Question 15

_____ chemicals require no chemical transformation to be carcinogenic.

Answer 15

Direct reacting

Question 16

Most chemicals are ______.

Answer 16

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

Question 17

What do chemical “promoters” do?

Answer 17

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

Question 18

What are some sources of Radiation carcinogenesis?

Answer 18

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

Question 19

What are 2 types of Viral oncogenesis?

Answer 19

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

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

Question 20

What factor aid in tumor immunity?

Answer 20

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.

Question 21

How can a tumor “evade” the immune system?

Answer 21

• 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

Question 22

What are the 5 clinical features of Neoplasia?

Answer 22

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.

Question 23

What is Grading?

Answer 23

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

Question 24

What is staging?

Answer 24

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

Question 25

How do labs diagnose cancer?

Answer 25

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