Cancer Cytogenetics

Question 1

Why do we study cytogenetics?

Answer 1

Important for diagnosis, prognosis, and therapy for patients w/ leukemia

Question 2

n = 23 c’somes

Answer 2

Haploid

Question 3

2n = 46 c’somes

Answer 3

Euploid

Question 4

Multiples of n (23, 46, 69)

Answer 4

Polyploidy

Question 5

3n = 69 c’somes

Answer 5

Triploid

Question 6

4n = 92 c’somes

Answer 6

Tetraploidy

Question 7

Gain or loss of c’somes

Answer 7

Aneuploidy

Question 8

Less than 46 c’somes

Answer 8

Hypoploid

Question 9

More than 46 c’somes

Answer 9

Hyperploid

Question 10

23-34 c’somes

Answer 10

Near haploid

Question 11

Cell w/ 46 c’somes and structural abnormalities

Answer 11

Pseudodiploid

Question 12

C’some w/ a translocation

Answer 12

Derivative c’some (der)

Question 13

Clonal proliferations of malignant leukocytes that arise initially in the bone marrow before disseminating to the peripheral blood, lymph nodes and other organs

Answer 13

Leukemia

Question 14

DNA double helix looped around histone proteins

Answer 14

Nucleosome

Question 15

Twisting of nucleosomes into a chromatin thread

Answer 15

Solenoid

Question 16

Name the 5 processes of the cell cycle and know what they do

Answer 16

G0: resting/quiescence
G1: growth before DNA synthesis
S: DNA synthesis
G2: growth
M: division occurs (PMAT)

Question 17

What cells are used for collection of specimens for c’some analysis?

Answer 17

Only cells in metaphase re used (chromatin is maximally condensed)
- Cells w/ high mitotic rate ar eusually chosen or cells that can be stimulated to divide (such as PB lymphs)

Question 18

What three things help cytogenetists identify c’somes?

Answer 18

• Overall size
• Placement of centromere
• Banding patterns

Question 19

P and Q arms

Answer 19

P arm = petite arm (shorter)

Q arm = longer arm

Question 20

What chemical is added to dividing cells to arrest them in metaphase?

Answer 20

Colcemid (derivative colchicine)

Question 21

Most common method of c’some banding

Answer 21

Giemsa banding

Question 22

Giemsa banding stains what areas of the c’somes?

Answer 22

A-T rich areas (not transcriptional aka late replicating)

Question 23

G-C rich areas of the c’some are also known as what areas?

Answer 23

Light areas
G-negative
Q-dull

Question 24

A-T rich areas of the c’some are also known as what areas?

Answer 24

Dark area
G-positive
Q-bright

Question 25

From the left to right name the karyotype nomenclature

Answer 25

- Modal number of chromosomes in the cell - Sex chromosome designation - Chromosomes - Arm - Band - Sub-band

Question 26

Regions, bands, and sub-bands are numbered staring where?

Answer 26

At the area closest to the centromere and get higher in value towards the telomere

Question 27

47, XX, +21

Answer 27

Female w/ Down Syndrome

Question 28

8 structural abnormalities

Answer 28

- Translocation - Robertsonian Translocation - Insertion - Inversion - Deletion - Duplication - Isochomosome - Marker chromosome

Question 29

C'some w/ a translocation

Answer 29

Derivative c'somes

Question 30

Occurs only on acrocentric c'somes; results the fusion of two c'somes

Answer 30

Robertsonian translocation

Question 31

Relatively rare b/c three separate breaks are required

Answer 31

Insertion

Question 32

- Interstitial involved two breaks and the loss of a segment between the breaks - Terminal involve only one break

Answer 32

Deletion

Question 33

Inversions that involve the centromere

Answer 33

Pericentric inversions

Question 34

Inversions that don't include the centromere

Answer 34

Paracentric inversions

Question 35

Division of c'somes is perpendicular to their long axis instead of parallel

Answer 35

Isochromosome

Question 36

Results from the breakage and rejoining of the end of a c'some (usually results in partial monosomy)

Answer 36

Ring c'some

Question 37

What is a molecular cytogenetic test that utilizes fluorescently labeled probes that are hybridized to metaphase or interphase cells

Answer 37

FISH (Flourescence in Situ Hybridization)

Question 38

You do not need ____ to perform FISH

Answer 38

Dividing cells

Question 39

____ results from multiple and sequential genetic mutations in a somatic cell. At some juncture, a critical mutation occurs and the cell becomes self-perpetuating (aka clonal)

Answer 39

Cancer

Question 40

What is a cell population derived from a single progenitor

Answer 40

Clone

Question 41

How do cytogenetics identify clones

Answer 41

- 2 or more cells contain the same structural abnormality or supernumerary marker chromosomes - 3 or more cells are missing the same chromosomes

Question 42

What aberration frequently found as the sole karyotype abnormality associated with a particular tumor? Aka "stem-line"

Answer 42

Primary aberration

Question 43

Aberration that is rarely found alone and develops in cells already carry a primary aberration

Answer 43

Secondary aberration

Question 44

t(8;21)(q22;q22.3) RUNX1T1 (ETO)/RUNXX1

Answer 44

AML w/ maturation

Question 45

t(15;17)(q24;q21.1) PML/RARA

Answer 45

Acute promyelocytic leukemia (APL or PML)

Question 46

inv(16)(p13q22)

Answer 46

AML w/ abnormal bone marrow eosinophils

Question 47

t(9;22)(q34;q11.2) CVR/ABL1 | know the two names

Answer 47

Chronic Myelogenous Leukemia (CML) and/or Philadelphia Chromosome

Question 48

t(16;16)(p13;q22)

Answer 48

AML with abnormal bone marrow eosinophils

Question 49

Who discovered that (9;22) is responsible for CML and that t(8;22) is responsible for AML?

Answer 49

Janet Rowley

Question 50

What is the drug to treat CML?

Answer 50

Imatinib

Question 51

The BCR-ABL Gene codes for ______ ______ that is perpetually turned "____"

Answer 51

Tyrosine Kinease; "on"

Question 52

The BCR-ABL gene leads to rapid progression through the cell cycle and thus rapid and uncontrollable cell ________.

Answer 52

Proliferation

Question 53

What prevents phosphorylation of the BCR-ABL TK?

Answer 53

Imatinib

Question 54

SNP allows for much greater resolution than what?

Answer 54

Karyograms and FISH

Question 55

Hyperdiploidy provides favorable prognosis for ALL in ______ but a poor prognosis in _____.

Answer 55

``` Favorable = children Poor = adults ```