PTEN test...is "positive" enough?

[Barbara2]

As we have learned, Herceptin antitumor activity is dependent on the presence of PTEN to be effective. I've read that we also need to test how much PTEN is in the breast tumor because no or low levels of PTEN don't respond well to herceptin.

The results of my PTEN testing showed "positive" but that is all it said. No percentiles or degrees were given. The test was done at the Targeted Molecular Diagnostics lab in Westmont, IL.

I'm wondering, then, how important is it to know how much PTEN is in the tumor? And could I get that information from the same testing that was done on the tissue, or would we need to re-test?

[Jean]

PTEN alteration plays a direct role in her2 tumors?
I have read theire is a connection however I thought it is
still tangential. I thought it was still being tested at
MD Anderson? I would also like to have the test performed
but what drug is there to target the PI-3 Kinase/PTEN pathway
for those that are negative?

Thanks,
Jean

[Barbara2]

Jean, here is something from my notes regarding a study at M.D. Anderson; March 2006 on P13K inhibitors. These findings were made in cell culture and mice studies, but were so promising that a Phase1/11 clinical trial was to start at M.D. Anderson in HER2-positive breast canacer patients whose disease had progressed despite Herceptin treatment.

"In this study, the researach group tested 7 different P13K inhibitors that are either used or under development for clinical trials. They found that one, RAD001 (everolimus), had better anititumor activity when combined with Herceptin than did Herceptin or RAD001 alone.

Another P13K inhibitor, TCN-P (triciribine), showed significant benefit when used in combination with Herceptin. Even with a low dose of TCN-P, the combination thereapy halted growth of PTEN-deficient HER-2popsitive breast tumors implanted in mice."

So, as I understand it, the PTEN marker may or may not turn out to be an indicator of response to Herceptin, in people. But some people are asking for this test. I just discovered that my onc ordered it before I started late herceptin. I recently called to see if I could have the test done, and they told me it had already been done.