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04-14-2004, 05:07 AM

Kristen,

Believe me, we actually do have a good sense of humor on the board. It has been a bit of a serious time on the board with a few situations that involve brain mets diagnoses and the recent loss of a few brave women.

I hope you were not put off by the posts relating to your "100% HER-2" comment. Most of the board participants are generally familiar with the "standard" measure for IHC and FISH testing.

Actually, your comment re "100% HER-2" is fairly close to mark. You indicated that your HER-2 status (by IHC-CB11 testing) was 2.6. An IHC +3 designation usually means that over 90% of the tumor cells within the sample "lit up" due to staining, thereby revealing the presence of HER-2 overexpression.

Your FISH measurement was marked as a 7.6 amplification. Although most folks have come to know FISH as an absolute "positive" or "negative" designation, the test is actually more detailed due to the fact that there exists a range of FISH positivity.

FISH uses molecular genetic techniques to create a fluorescent DNA probe that produces a bright microscopic signal when it selectively attaches to the gene specific complementary DNA (e.g., HER-2). A different DNA probe attaches itself to the chromosome 17 centromere (CEP 17). The signals appear as orange and green fluorescent colors for the HER-2 gene and chromosome 17, respectively. This enables a ratio of HER-2 to chromosome 17 signals to be calculated.

A HER-2/CEP 17 ratio equal to or greater than 2.0 is considered amplified or "positive" by FISH. At a ratio of 7.6, you are clearly FISH positive and then some. Herceptin should work quite well for you.

Good luck with your clinical trial and let us know how things go.

04-14-2004, 05:07 AM	#8
Paul Guest Posts: n/a	Kristen, Believe me, we actually do have a good sense of humor on the board. It has been a bit of a serious time on the board with a few situations that involve brain mets diagnoses and the recent loss of a few brave women. I hope you were not put off by the posts relating to your "100% HER-2" comment. Most of the board participants are generally familiar with the "standard" measure for IHC and FISH testing. Actually, your comment re "100% HER-2" is fairly close to mark. You indicated that your HER-2 status (by IHC-CB11 testing) was 2.6. An IHC +3 designation usually means that over 90% of the tumor cells within the sample "lit up" due to staining, thereby revealing the presence of HER-2 overexpression. Your FISH measurement was marked as a 7.6 amplification. Although most folks have come to know FISH as an absolute "positive" or "negative" designation, the test is actually more detailed due to the fact that there exists a range of FISH positivity. FISH uses molecular genetic techniques to create a fluorescent DNA probe that produces a bright microscopic signal when it selectively attaches to the gene specific complementary DNA (e.g., HER-2). A different DNA probe attaches itself to the chromosome 17 centromere (CEP 17). The signals appear as orange and green fluorescent colors for the HER-2 gene and chromosome 17, respectively. This enables a ratio of HER-2 to chromosome 17 signals to be calculated. A HER-2/CEP 17 ratio equal to or greater than 2.0 is considered amplified or "positive" by FISH. At a ratio of 7.6, you are clearly FISH positive and then some. Herceptin should work quite well for you. Good luck with your clinical trial and let us know how things go.