Sunday, April 29, 2012

My triple negative tumor is different from your triple negative tumor

Classifying breast cancer as triple negative just tells you what your tumor is not. It is not sensitive to estrogen, progestins, or does it over express the Her2 oncogene. It is akin to classifying an animal as something that does not have feathers, does not have antennae, and is not green. One is left with a whole bunch of animals that it could be.
The greatest recent advances in cancer therapy have been in targeted therapy (versus early chemotherapy in which all fast growing cells are killed in the hope that the cancer cells will be killed too: this is what was offered to me). What should be targeted in TNBC? Recently scientists tried to characterize 100 tumors from 100 different TNBC patients looking for gene sequences in common in hopes of finding something to target. They found very little in common. Even worse, the tumor cells were not the same even in a given patient. In the recent past, PARP inhibitors have been used successfully in some patients, notably ones who have the BRAC1 gene deficiency which is associated with some cases of TNBC. But they have not been effective against all TNBC patients with  mets. Various researchers have had conflicting successes with identifying a factor that may in the future give us quadruple negative breast cancer (or at least the name): androgen. Healthy breast cells are sensitive to androgen as are cancer cells that still haven't differentiated too far from the original tissue. Initially TNBC seems more aggressive as defined by growing faster that are androgen positive but it is not clear if androgen positive tumors have a greater tendency for metastasis. As far as I know, there have been no clinical trials for this though the drug itself should be easy enough to find. Perhaps the androgen blockers used against prostate cancer could be used.


I saw this on a T-shirt recently. So easy to fall in this trap though usually I use more than one example. To soothe myself over the past few years, I have tried to look for evidence that TNBC is not as fatal in post menopausal women as it is in premenopausal. There have been no specific studies I can find. There are studies that indicate BC in general is more deadly in younger women giving the reason is that it is more likely to be hormone negative but nothing that compares pre versus post with the same tumors. Frustrating. So I am left with anecdotal evidence which is this: ladies with TNBC and are postmenopausal who blog are still all alive. The younger ones who blog are not all still alive. Drawing conclusions from blogsphere can be misleading. I could conclude that most TNBC patients are white because I haven't seen many blogs from African-American patients but according to statistics, this would be very wrong.

My dogwood out my window
A record cold today but hopefully this should be the end of frost for a while. My legs are exhausted from so much running. I hope to have enough energy to tackle more projects today. Meanwhile, Shanna's family slowly inches home. When we had two toddlers, we would travel long distances at night because Josh during the day would become intolerable if confined for more than a few minutes. Throw a baby in the mix and one has the  recipe for not a fun time. They have just one more trip to endure and that will be a toughie as moving all their possessions will be involved.

1 comment:

Holly said...

my paternal grandparents were 1/2 African American.


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