interpreting HER2 FISH results

Cheesequake

Hey all, my pathology report shows the following for HER2. Anybody have any idea how to decipher this? Thanks in advance!

Comments: Ductal Carcinoma DNA FISH PROBE

Comments: LSI HER-2 (17q11.2-q12) SO / CEP 17 (D17Z1) SG, PathVysion HER-2 DNA Probe Kit from Vysis (an Abbott Laboratories Company)

HER2 SIGNALS, TOTAL, BLD/TISS, MOLGEN

221

CEP17 SIGNALS, TOTAL, BLD/TISS, MOLGEN

97

HER-2/CEP17 SIGNALS, BLD/TISS, MOLGEN

2.28

INTERPRETATION

Comments: POSITIVE (Dual-probe HER2/CEP17 >= ratio 2.0; with an average HER2 copy number >=4.0 signals/cell).

debiann

I'm not certain, and I'm sure someone more knowledgeable will be along to help you, but HER2+ is the "overexpression of the HER 2 receptor". I would think that an "average HER2 copy number" may mean you are not going to be considered her2+, but I could be wrong.

Cheesequake

Thanks debiann. That final sentence of the report says "POSITIVE," and they did tell me I'm HER2+. I'm just wondering if the rest of the numbers give any indication of HOW positive it is.

It seems to say my ratio is greater than or equal to 2.0 (the line above it indicates that ratio is 2.28), with an average copy number of greater than or equal to 4.0 signals per cell. But I don't know what that means!

So much to learn....

windingshores

• Positive HER2 amplification: FISH ratio higher than 2.2 or HER2 gene copy greater than 6.0.
• Equivocal HER2 amplification: FISH ratio of 1.8-2.2 or HER2 gene copy of 4.0-6.0.
• Negative HER2 amplification: FISH ratio lower than 1.8 or HER2 gene copy less than 4.0.

Some labs consider a positive result for the ratio to be over 2.0 . Either way you are positive, even though your gene copy is less than 6, because your ratio is 2.28.

windingshores

Here is another one, with the 2.0 cut off:

IHC 3+ denotes a positive test if membrane staining is complete and intense in >10% cells that demonstrate circumferential membrane staining (a chicken wire-like pattern). For dual-probe ISH tests, a HER2/CEP17 ratio of ≥2.0 (previously ≥2.2) and an average HER2 gene copy number of ≥4.0 are positive. Additionally, if the HER2/CEP17 ratio is <2.0 and the average HER2 copy number is ≥6.0, the test is positive. In rare situations, a HER2/CEP17 ratio ≥2.0 and an average HER2 copy number of <4.0 are noted as being positive in the updated guideline. A single-probe ISH test is considered HER2-positive if the HER2 gene copy number is ≥6.0 signals per cell. - See more at: http://www.targetedonc.com/articles/ascocap-release-new-guidelines-for-her2-testing-in-breast-cancer/2#sthash.JekUwBel.dpuf

Italychick

andicbd I am in the same boat you are. Everything was equivocal. Finally, after a third level of testing, they determined I am something like 2.4 her+. I did read some studies online that say with a smaller tumor (mine was 1.3 cm IDC) that the her ratio can be lower, but it still is important to take the Herceptin because there weren't as many cells to count or something like that. My oncologist recommended Herceptin because it is known as a miracle drug and if there is a chance it can work, do it. So I am doing it and monitoring my heart ejection fraction every three months. Mine was classified as low level amplification. It also said to monitor patient on Herceptin because two of my ratios showed Her2, but one of the ratios was still equivocal.

Sorry there aren't any easy answers. It basically came down to me trusting my oncologist and taking the Herceptin. Best of luck whatever you decide!

Cheesequake

Thanks windingshores and Theresa for your input - that helps a lot. It seems like I'm "low level amplification" like you, Theresa.