1d. FISH and Microarray

Question 1

To determine the mechanism of an imbalance detected on aCGH what method should be used?

Answer 1

FISH

Question 2

If you send a HER2 FISH assay hybridization part to a different lab, how should you perform the FISH assay profecienct testing?
how frequesnt should it be?

Answer 2

Perform an alternative HER2 FISH proficency test instead of the CAP formal proficency test.
Semiannually

Question 3

How many images and how long should a clinical lab retain for FISH assay?

Answer 3

For cancer: At least 1 cell for 10 years
For constitutional: At least 2 cells for 20 years

Question 4

How long should a HER2 FISH assay be fixed in 10% neutral buffered formaline?

Answer 4

6-72hrs

Question 5

How many samples should a clinical lab use to validate a FDA approved HER2 FISH assay?

Answer 5

20 for FDA-approved Tests
40 for Lab-Developed Tests

Question 6

How many copies of HER2 gene in one nucleus is amplifiction?

Answer 6

Ratios of HER2 to CEP17
>2.2 positive, <1.8 Negative
>=Six signals positive, <Four signals negative

Question 7

What are the two main weaknesese of Microarray?

Answer 7

Can’t detect structural variants (SV) eg balanced translocations as well as can’t detect mechanism
suboptimal for low tumor content

Question 8

Break apart probes in what genes can be used?

Answer 8

ALK rearengmets: dual color break apart
MLL rearengments single color breakpapart

Question 9

How many probes do breakapart probes made of?

Answer 9

made of two probes