Cancer Cytogenetics Lecture

Question 1

Why do we study cytogenetics?

Answer 1

Important for proper diagnosis, prognosis, and therapy for patients with leukemia

Question 2

n or 23

Answer 2

Haploid

Question 3

2n or 46

Answer 3

Euploid

Question 4

multiples of n (23, 46, 69…)

Answer 4

Polyploidy

Question 5

3n or 69 chromosomes

Answer 5

Triploid

Question 6

4n or 92 chromosomes

Answer 6

Tetraploidy

Question 7

Gain or loss of chromosome

Answer 7

Aneuploidy

Question 8

less than 46 chromosomes

Answer 8

Hypodiploid

Question 9

More than 46 chromosomes

Answer 9

Hyperdiploid

Question 10

*

Answer 10

Near haploid

Question 11

*

Answer 11

Pseudodiploid

Question 12

*

Answer 12

Derivative chromosome

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 chromosome analysis?

Answer 17

only cells in metaphase (cells with a high mitotic rate)

Question 18

How are chromosomes identified?

Answer 18

• overall size
• placement of centromere
• banding patterns

Question 19

P arm-

q arm

Answer 19

p arm petite arm - shorter arm

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 chromosome banding

Answer 21

Giemsa Banding

Question 22

Giemsa Banding stains what areas of the chromosomes?

Answer 22

A-T rich areas

Question 23

A-T rich regions of the chromosome are also known as what areas (3)

Answer 23

Dark areas
G-Positive
Q-Positve

Question 24

G-C rich regions of the chromosome are knows as what areas? (3)

Answer 24

Light Areas
G-Negative
Q- Dull

Question 25

From 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 number starting where?

Answer 26

at the area closes to the centromere and get higher in value towards the telomere

Question 27

47, XX, +21

Answer 27

Female with Down Syndrome

Question 28

Structural Abnormalities | 8

Answer 28

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

Question 29

Chromosome with a translocation

Answer 29

Derivative Chromosome

Question 30

Occurs only on acrocentric chromosomes; results the fusion of two chromosomes

Answer 30

Robertsonian Translocation

Question 31

Relatively rare because 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 involve the centromere

Answer 33

Pericentric Inversions

Question 34

Inversions that do not include the centromere

Answer 34

Paracentric Inversions

Question 35

Division of chromosomes is perpendicular to their long axis instead of parallel

Answer 35

Isochomosome

Question 36

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

Answer 36

Ring Chromosome

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 with 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 with 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 kinase | "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

**Three ways that that chromosomes are identified by cytogenetists?

Answer 55

?

Question 56

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

Answer 56

``` favorable = children poor = adults ```