HER2 Support Group Forums - View Single Post - Cancers Can Vanish Without Treatment, but How?

gdpawel · 12-28-2009, 07:35 AM

Hopeful

The Oncotype DX test looks at 21 genes that influence the behavior of breast cancer cells. The MammaPrint has some superiority over the Oncotype DX because it looks at the expression of 70 genes (as opposed to only 21) linked to breast cancer with an accuracy level of 96.7% as determined by a study published in the NEJM.

While these tests have been shown to be superior over conventional assessment of risk of future metastatic disease, one gets more accurate information when using intact RNA isolated from "fresh" tissue than from using degraded RNA, which is present in paraffin-fixed tissues.

The NCI has a huge lab working on microarrays to look for patterns of mRNA and protein expression which are predictive of chemotherapy response. They spent two years trying to find patterns which correlated using the NCI's various established ovarian cell-lines.

They thought they had something, but when they started to apply them to "fresh" tumor specimens, none of the results in the cell-lines was applicable to the "fresh" tumors. Everything they worked out in the cell-lines was not worth anything and they had to start over from square one.

However, the limitations and non-applicability of the NCI efforts failed to realize that the way to identify informative gene expression patterns is to have a "gold standard" and the (cell-death) cell culture assays are by far the most powerful, efficient, useful "gold standard" to have, adding the potential value of the assays to individual cancer therapy.

In regards to "accuracy" of a test. The CellSearch System (like PET imaging) is a test that can be done after therapy to monitor results. A friend went to a symposium devoted entirely to the CellSearch technology. He came out of it thinking it's not of value in "selecting" therapy and it is really not all that accurate.

The cut off is 5 tumor cells. Less than 5 means that things are going well. More than 5 means that things are going poorly. But you can see that the difference between 4 and 6 is not all that great. It could perhaps, be useful as an adjunct to traditional methods for following tumor response, such as xrays, blood tests, MRIs, history, physicial exam, etc.

12-28-2009, 07:35 AM	#7
gdpawel Senior Member Join Date: Aug 2006 Location: Pennsylvania Posts: 1,080	Re: Cancers Can Vanish Without Treatment, but How? Hopeful The Oncotype DX test looks at 21 genes that influence the behavior of breast cancer cells. The MammaPrint has some superiority over the Oncotype DX because it looks at the expression of 70 genes (as opposed to only 21) linked to breast cancer with an accuracy level of 96.7% as determined by a study published in the NEJM. While these tests have been shown to be superior over conventional assessment of risk of future metastatic disease, one gets more accurate information when using intact RNA isolated from "fresh" tissue than from using degraded RNA, which is present in paraffin-fixed tissues. The NCI has a huge lab working on microarrays to look for patterns of mRNA and protein expression which are predictive of chemotherapy response. They spent two years trying to find patterns which correlated using the NCI's various established ovarian cell-lines. They thought they had something, but when they started to apply them to "fresh" tumor specimens, none of the results in the cell-lines was applicable to the "fresh" tumors. Everything they worked out in the cell-lines was not worth anything and they had to start over from square one. However, the limitations and non-applicability of the NCI efforts failed to realize that the way to identify informative gene expression patterns is to have a "gold standard" and the (cell-death) cell culture assays are by far the most powerful, efficient, useful "gold standard" to have, adding the potential value of the assays to individual cancer therapy. In regards to "accuracy" of a test. The CellSearch System (like PET imaging) is a test that can be done after therapy to monitor results. A friend went to a symposium devoted entirely to the CellSearch technology. He came out of it thinking it's not of value in "selecting" therapy and it is really not all that accurate. The cut off is 5 tumor cells. Less than 5 means that things are going well. More than 5 means that things are going poorly. But you can see that the difference between 4 and 6 is not all that great. It could perhaps, be useful as an adjunct to traditional methods for following tumor response, such as xrays, blood tests, MRIs, history, physicial exam, etc.