Herceptin question

The way my mom's onc described it, a Her2 cancer cell is different to all others, in that, Her2 Cancer cells have little doors on them that are always open (that chemo alone will not close) which allows the Her2 to begin overexpressing itself.  This is when the cancer grows or spreads.  Herceptin binds to the cancer cell and closes the little door so that it stops it from getting out and growing again.  But when you combine it with chemo, the door has been closed and the chemo is able to destroy the cancer cell, as it is being prevented (via Herceptin) from overexpress itself more.  Thus, chemo can then do it's job. 

Whereas if you did chemo alone, like it was before herceptin was known.  The cancer still gets out even though it is being destroyed by chemo.  The door to the overexpression of Her2 needs to be shut.

I probably didn't say that as articulate as the Onc did, but it helped me understand the process of Herceptin.  I hope it does the same for you too.

Michelle

I believe the purpose of herceptin depends on what stage you are in.  I am Stage 1 and had a mastectomy, chemo and herceptin for one year.

It is not totally clear how herceptin works.  It is thought that when binding to the Her2 receptors on the cell surface, the herceptin may somehow signal the immune system to destroy the cell.

So in my case, the oncologist told me after mastectomy I was grossly clear of cancer.  After chemo I was microscopically clear.  The herceptin was my warranty to stay clear (finding any stray cell, binding to it, and having the immune system destroy it).

Dear Joni,

You may want to go directly to the Genentech website for good information on Herceptin (they make it).  My understanding is that the Her2/neu protein on the surface of the cell signals the cancer cell to divide (cell mitosis).  When it is "overexpressed", (i.e., it is all OVER the cell due to the mutation in the DNA of the cancerous cell) that cancer grows more quickly and is more mutated.  The Herceptin binds to these receptors (closing the door as described above) and shuts down that growth rate.  Also, the binding of the Herceptin to the receptors on the surface makes the cancer cell look funny to the immune system, so that it will attack and kill the cell. (Hence Herceptin is called an "immunotherapy".  It activates the body's own immune system to kill the cancer cell.)

It is proven to prevent a significant amount of recurrences.  It doesn't work in all cases.  But it is a wonderful weapon for Her2+ women.

 So, to answer your question, the Herceptin is acting on any remaining cancer cells.  It therefore prevents recurrence.  We do not yet have the technology to detect cancer at the individual cellular level, so they determine the effectiveness of new treatments by studying large groups and seeing if there is a statistically significant drop in the number of recurrences that could be expected without the new treatment.  I believe that Herceptin has cut in half the number of expected recurrences.

Best of luck,

Hope M.