Genetic studies of cancer FISH+ MRD

Question 1

clonal aberration

Answer 1

visible chromosome translocation

Question 2

chromosome aberrations used for (X3)

Answer 2

diagnose particular tumour type, determine prognosis, Predict response to therapy

Question 3

Cytogenetics: Leukaemia

Answer 3

cells cultured + Karyotyped (subtle changes )

Question 4

Trisomy

Answer 4

3 copies of chromosome eg downs 21

Question 5

FISH: fused signal

Answer 5

Translocation

Question 6

Uveal melanoma mutation

Answer 6

Ureal Melanoma : Loss of chr 3+gain of 8 = most likely to die

Question 7

Spectral Kangotyping Benefits

Answer 7

Identify subtle translocations

Question 8

Comparative Genome Hybridization is used to

Answer 8

Detection Of chromosome losses + gains in tumour DNA

Question 9

How array aCGH works (method)

Answer 9

1 )Reference + tumour DNA labelled red or green
2) Hybndize onto Chip containing DNA capture probes
3) measure Red: Green ratio

Question 10

CGH Principle

Answer 10

Tumour+ Ref DNA compete for hybridization on metaphase spread
measure ratio

Question 11

CGH results

Answer 11

Excess tumour colour= Gain in DNA
Excess Ref = loss or DNA

Question 12

aCGH results

Answer 12

tumour coloured dot e.g red = DNA amplification at that region

Question 13

Benefits of aCGH

Answer 13

aCGH= higher resolution

Question 14

Herceptin FISH

Answer 14

Acts on Her2 gene = Over expression gives better response
FISH Prevents over treatment of lower risk patients (not effective enough)

Question 15

CISH

Answer 15

same as FISH but chromogenic signal (permanent) labelled to nucleotide

Question 16

CISH visualization

Answer 16

light microscope + can be overlaid with histology

Question 17

CISH Principles (her2)

Answer 17

same as IHC
DNP labelled Her-2 probe + DIG labelled Chr 17 probe
detected by anti- DNP / anti - DIG
= indirect

Question 18

FISH v IHC pros + cons

Answer 18

FISH: Better test but expensive
HC: easy, cheap but subject to interpretation

Question 19

what is MRD?

Answer 19

Detection of tumour cells after therapy

Question 20

Aim of MRD

Answer 20

reduce, maintain or increase therapy

Question 21

RT-PCR to detect translocations method

Answer 21

3 primers : 2 (forward and reverse) on genes in regions always present in fusion transcript
1 on location present in both normal t mutation

Question 22

Molecular Relapse

Answer 22

Relapse detected prior to standard diagnostic levels of disease

Question 23

How molecular relapse detected

Answer 23

molecular relapse derected by calculating ratio between mutation + total signa

Question 24

Benefits of qPCR (relapse

Answer 24

Predicts which patients to have likely molecular relapse = earlier therapy