neoplasia

Question 1

What does monoclonal mean in neoplasia?

Answer 1

Neoplastic cells are derived from a single mother cell.

Question 2

How is clonality historically determined?

Answer 2

By analyzing glucose-6-phosphate dehydrogenase (G6PD) enzyme isoforms.

Question 3

What is the normal ratio of G6PD isoforms in polyclonal tissues?

Answer 3

1:1

Question 4

What is the difference in G6PD isoform ratio between hyperplasia and neoplasia?

Answer 4

Hyperplasia is polyclonal (1:1 ratio), while neoplasia is monoclonal (only one isoform).

Question 5

How is B lymphocyte clonality determined?

Answer 5

By analyzing the immunoglobulin (Ig) light chain phenotype (kappa or lambda)

Question 6

What is the normal kappa to lambda light chain ratio in B cells?

Answer 6

3:1.

Question 7

How does the kappa to lambda ratio change in lymphoma?

Answer 7

The ratio becomes >6:1 or is inverted (e.g., 1:3), indicating monoclonality.

Question 8

What distinguishes benign tumors from malignant tumors?

Answer 8

Benign tumors: Localized, do not metastasize.
Malignant tumors: Invade locally and can metastasize

Question 9

What determines tumor nomenclature?

Answer 9

The lineage of differentiation (type of tissue) and whether the tumor is benign or malignant.

Question 10

How many cell divisions occur before the earliest clinical symptoms of cancer?

Answer 10

Approximately 30 divisions.

Question 11

What does a Pap smear detect?

Answer 11

Cervical dysplasia (CIN) before it becomes carcinoma

Question 12

What does mammography detect?

Answer 12

In situ breast cancer (e.g., DCIS) before it invades.
Invasive carcinoma before it becomes clinically palpable

Question 13

What are carcinogens?

Answer 13

Agents that damage DNA, increasing cancer risk (e.g., chemicals, viruses, radiation)

Question 14

What are proto-oncogenes?

Answer 14

Genes essential for cell growth and differentiation. Mutations form oncogenes, leading to unregulated cellular growth.

Question 15

What are the categories of oncogenes?

Answer 15

Growth factors (e.g., PDGFB in astrocytoma)
Growth factor receptors (e.g., HER2/neu in breast cancer)
Signal transducers (e.g., ras)

Question 16

What cancer is associated with aflatoxins?

Answer 16

Hepatocellular carcinoma
Derived from Aspergillus, which can contaminate stored rice and grains.

Question 17

What cancer is caused by alkylating agents?

Answer 17

Leukemia/lymphoma.
Side effect of chemotherapy

Question 18

Name three cancers associated with alcohol.

Answer 18

Squamous cell carcinoma of oropharynx and upper esophagus
Hepatocellular carcinoma

Question 19

What cancers are linked to arsenic exposure?

Answer 19

Squamous cell carcinoma of skin
Lung cancer
Angiosarcoma of the liver
Arsenic is present in cigarette smoke.

Question 20

What cancers are associated with asbestos?

Answer 20

Lung carcinoma
Mesothelioma
Exposure to asbestos is more likely to lead to lung carcinoma than mesothelioma.

Question 21

What cancer is caused by naphthylamine?

Answer 21

Urothelial carcinoma of the bladder.
Derived from cigarette smoke.

Question 22

What cancer is linked to nitrosamines?

Answer 22

Stomach carcinoma.

Question 23

What cancer is caused by naphthylamine?

Answer 23

Urothelial carcinoma of the bladder

Question 24

What cancer is associated with vinyl chloride?

Answer 24

Angiosarcoma of the liver.
Occupational exposure; used to make PVC for pipes.

Question 25

What cancers are linked to exposure to nickel, chromium, beryllium, or silica?

Answer 25

Lung carcinoma.

Question 26

What cancers are associated with EBV (Epstein-Barr Virus)?

Answer 26

Nasopharyngeal carcinoma Burkitt lymphoma CNS lymphoma in AIDS

Question 27

What cancer is linked to HHV-8?

Answer 27

Kaposi sarcoma.

Question 28

What cancer is linked to HTLV-1?

Answer 28

Adult T-cell leukemia/lymphoma.

Question 29

Which high-risk HPV subtypes are associated with cancer?

Answer 29

Subtypes 16, 18, 31, 33. Causes squamous cell carcinoma of vulva, vagina, anus, and cervix; adenocarcinoma of the cervix.

Question 30

What cancers are associated with ionizing radiation?

Answer 30

AML (Acute Myeloid Leukemia) CML (Chronic Myeloid Leukemia) Papillary carcinoma of the thyroid Generates hydroxyl free radicals.

Question 31

What cancers are linked to non-ionizing radiation (e.g., UV sunlight)?

Answer 31

asal cell carcinoma Squamous cell carcinoma Melanoma of the skin Results in the formation of pyrimidine dimers in DNA, normally excised by restriction endonuclease.

Question 32

What is the inactive state of ras?

Answer 32

Ras is associated with growth factor receptors in an inactive GDP-bound state.

Question 33

How is ras activated?

Answer 33

Receptor binding causes GDP to be replaced with GTP, activating ras. Activated ras sends growth signals to the nucleus.

Question 34

How does ras return to its inactive state?

Answer 34

Ras inactivates itself by cleaving GTP to GDP; this process is augmented by GTPase activating protein.

Question 35

What happens in ras mutations?

Answer 35

Mutated ras inhibits the activity of GTPase activating protein, prolonging the activated state of ras and increasing growth signals

Question 36

What is the role of cyclins and cyclin-dependent kinases (CDKs)?

Answer 36

Cyclins and CDKs form a complex that phosphorylates proteins, driving the cell through the cell cycle.

Question 37

Give an example of a cyclin-CDK complex and its function.

Answer 37

The cyclin D/CDK4 complex phosphorylates the retinoblastoma (Rb) protein, promoting progression through the G1/S checkpoint.

Question 38

What is the role of tumor suppressor genes?

Answer 38

Tumor suppressor genes regulate cell growth and decrease the risk of tumor formation

Question 39

Name two classic tumor suppressor genes.

Answer 39

p53 and Rb (retinoblastoma).

Question 40

What is the function of p53?

Answer 40

p53 regulates the progression of the cell cycle from G1 to S phase.

Question 41

What is the function of PDGFB and its associated tumor?

Answer 41

Function: Platelet-derived growth factor. Mechanism: Overexpression, autocrine loop. Associated Tumor: Astrocytoma.

Question 42

What tumor is associated with ERBB2 (HER2/neu) and its mechanism?

Answer 42

Function: Epidermal growth factor receptor. Mechanism: Amplification. Associated Tumor: Subset of breast carcinomas.

Question 43

What is the role of RET and its associated conditions?

Answer 43

Function: Neural growth factor receptor. Mechanism: Point mutation. Associated Tumors: MEN2A, MEN2B, and sporadic medullary carcinoma of the thyroid.

Question 44

What type of tumor is linked to KIT and its mechanism?

Answer 44

Function: Stem cell growth factor receptor. Mechanism: Point mutation. Associated Tumor: Gastrointestinal stromal tumor.

Question 45

What are the key features of the RAS gene family?

Answer 45

Function: GTP-binding protein. Mechanism: Point mutation. Associated Tumors: Carcinomas, melanoma, and lymphoma.

Question 46

What is the significance of ABL in oncogenesis?

Answer 46

Function: Tyrosine kinase. Mechanism: t(9;22) translocation with BCR. Associated Tumors: Chronic myeloid leukemia (CML) and some types of acute lymphoblastic leukemia (ALL).

Question 47

What tumor is associated with c-MYC, and what is the genetic alteration?

Answer 47

Function: Transcription factor. Mechanism: t(8;14) involving IgH. Associated Tumor: Burkitt lymphoma

Question 48

What tumor is associated with N-MYC?

Answer 48

Function: Transcription factor. Mechanism: Amplification. Associated Tumor: Neuroblastoma.

Question 49

What tumor is associated with L-MYC?

Answer 49

Function: Transcription factor. Mechanism: Amplification. Associated Tumor: Small cell lung carcinoma.

Question 50

What is the function of CCND1 (Cyclin D1) and its associated cancer?

Answer 50

Function: Cyclin. Mechanism: t(11;14) involving IgH. Associated Tumor: Mantle cell lymphoma.

Question 51

What tumor is associated with CDK4 and its mechanism?

Answer 51

Function: Cyclin-dependent kinase. Mechanism: Amplification. Associated Tumor: Melanoma.