Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Biotech / Medical : Ligand (LGND) Breakout! -- Ignore unavailable to you. Want to Upgrade?

To: Vector1 who wrote (15044)	2/13/1998 11:23:00 PM
From: squetch	Read Replies (1) \| Respond to of 32384

>>The discussion centered around the isssue that many promising cancer drugs in Xenografted tumors in Mice do not perform in humans. The primary reason is two fold.<< V1, This paper mention a third issue. Xenografted tumors also lacked the cellular architecture of the natural tumor environment. So in xenograft tumors you can only look at effect on tumor. This has implications if the therapy were to interact w/ the surrounding environment. The paper also says the NMU model has been used extensively to analyze the effects of antiestrogens, such as Tamox. and raloxifen, on prevention of mammary carcinogenesis and therapy of established breast tumors. Definitely secondary tumor growths.

To: Vector1 who wrote (15044)	2/14/1998 4:42:00 AM
From: Henry Niman	Read Replies (2) \| Respond to of 32384

V1, I'll give more details later, but the PNU rat model treats (IV injection) the mice with a carcinogen, PNU, which causes them to develop breast cancer. The tumors are adenocarcinoma, like the most frequent type of human breast cancer, and is a much more "natural" process. Targretin previously has been shown to PREVENT these tumors from developing (as has Tamoxifen), but in this study they allowed the tumors to develop, and then treated the rats. The results were stunning (the breast tumors disappeared in 72% of the rats). Thus, in this model, the drug is used to treat a rat tumor that develops from exposure to a carcinogen. In xenografts, a human tumor is placed in immunocompromised animals (usually nude mice) and then treated (a fairly artificial situation).