Neoplasms9-13

Question 1

Which protooncogene is associated with a t(14:18) translocation?

Answer 1

Bcl-2

Question 2

BRAF V600E mutations

Answer 2

Melanoma (40-60%)

Question 3

What is the function of BRAF?

Answer 3

BRAF is a protein kinase involved in the activation of signaling pathways for melanocyte proliferation.

Question 4

What type of necrotic pathology would you see after ischemia to the brain?

Answer 4

Liquefactive necrosis

Lysozymes has completely digested and removed all of the necrotis tissue and formed a cystic cavity.

Question 5

Name the genes (1, 2, & 3) involved in the adenoma to carcinoma sequence.

Normal epithelium(1)>Early adenoma(2)>Late adenoma(3)>Adenocarcinoma

Answer 5

1. APC: tumor suppresor; located on chromosome 5; causes the formation of a small polyp
2. K-RAS: proto-oncogene; increases the size of polyps
3. p53: tumor supressor; allows cells with genomic errors to enter cell cycle; last hit (along with DCC gene)

Question 6

List the four (4) non-neoplastic colonic polyps.

Answer 6

1. Hyperplastic: well differentiated mucosal cells forming glands and crypts
2. Hamartomatous: mucosal glands, smooth muscle and connective tissue
3. Inflammatory: regenerating intestinal mucosa
4. Lymphoid: intestinal mucosa infiltrated with lymphocytes

Question 7

Pathogenesis:

Tumor lysis syndrome

Answer 7

When tumors with a high cell turnover rate are treated with chemotherapy, intracelluar content (potassium, phosphorous, & uric acid) spills over into the serum.

Question 8

Diagnosis:

Autosomal recessive, UV specific endonuclease deficiency

Answer 8

xeroderma pigmentosum

Question 9

Treatment:
Tumor lysis syndrome

Answer 9

1. Hydration
2. Alkalinize the urine
3. Allopurinol –> to reduce uric acid production during the breakdown of tumor cells.

Question 10

Name the metabolite of tumor nucleic acid that is soluble at physiological pH, but can precipitate in the kidney.

Answer 10

Uric acid is a metabolite of tumor nucleic acid. It can precipitate in the acidic environment of the renal distal tubule and collecting duct.

Question 11

What is the best prognostic indicator for patients with malignant melanoma?

Answer 11

Breslow thickness: the measure of depth invasion (vertical)

Question 12

You biopsy an abnormal lymph node and see monoclonal T-cell receptor gene rearrangements. What is this indicative of?

Answer 12

A monoclonal lymphocytic proliferation is strong evidence of MALIGNANCY.

Question 13

What determines the prognosis of colorectal adenocarcinoma?

Answer 13

The STAGE, or extent of tumor expansion, NOT the grade, or degree of tumor differentiation!

Question 14

Proto-oncogenes vs. Anti-oncogenes

ras, N-myc, ERB-B1, ERB-B2, TGF_, sis, abl

Answer 14

proto-oncogenes (tumor promoters)

Question 15

Proto-oncogene vs. Anti-oncogene

BRCA-1, BRCA-2, NF-1, APC/_-catenin, DCC, p53, RB, WT-1

Answer 15

anti-oncogenes (tumor supressors)

Question 16

Pathogenesis:

How do aflatoxins cause hepatocellular carcinoma?

Answer 16

High levels of dietary aflatoxin exposure is associated with a C–>T transversion in the p53 gene. p53 mutations have been identified in most individuals with hepatocellular carcinoma.

Question 17

What is the name of the molecule responsible for cachexia (wasting syndrome) in cancer patients

Answer 17

TNF-_

Another name for TNF-_ is cachectin.

Question 18

Clinical Manifestation:
Cachexia

Answer 18

1. anorexia
2. malaise
3. anemia
4. weight loss
5. generalized wasting

Question 19

Myeloproliferative disorders associated with JAK2 mutations

Answer 19

chronic myeloproliferative disorders

1. Polycythemia vera
2. Essential thrombocytosis
3. Primary myelofibrosis

Question 20

Myeloproliferative disorders associated with persistant activation of signal transducers and activator of transcription (STAT) proteins

Answer 20

Chronic myeloproliferative disorders; associated with JAK2 mutations