Why do I read posts saying hercept not working

[Lani]

AM travelling tomorrow and packing tonight, but let me try to answer a few questions.
NO--we don't want the puppy to get out. Chemotherapy is like carpet bombing (targetted therapy with monoclonal antibodies is like using smart-bombs) but both, but particulary chemo act like weedkiller. Once one clonal group of cancer cells is killed by the treatment another group (like a weed) has no competition for nourishment and grows even more. That is like making the puppy grow taller faster.

Neoadjuvant therapy is usually only given if the tumor is big enough to follow its shrinkage with serial imaging--those who are Stage I do not qualify.

and 'lizbeth--no Herceptin does not work for everyone who is her2 amplified.

There are both de novo resistant tumors and tumors that acquire resistance with treatment ie, seek another pathway. I was referring to the latter mostly.

An example of the former are tumors with a truncated form of her2 that herceptin does not bind. These should be sensitive to Lapatinib , other examples might be a her2 that herceptin doesn't bind to easily and these may be sensitive to pertuzumab. There may also be some tumors so coated with Muc1 a gooey mucinous substance that the herceptin can't get to the her2 receptor. I am sure there are more examples of de novo resistance.

Back to packing for now.