Immunodeficient mice are a necessity for xenograft experiments, as functional murine immune systems will lead to effects that are not comparable with the human microenvironment. When we do xenografts commercially (http://altogenlabs.com/xenograft-models/) we use immunodeficient mice, but if you don't have already immunodeficient ones, then cyclosporin treatment can help suppress the immune response.
It is an interesting question. In theory, it may be possible to suppress the immune system (e.g. with corticosteroids) and engraft human tumor cells. However, the immunosuppressant drugs will decrease inflammation, hence this will affect the tumor biology. But it would be very interesting to try. Another possibility is the use of syngeneic models (using mouse tumor cells), or a humanized mouse model.
No immunosuppression is needed, use the same strain as where tumor cells come from. I believe the reason you do not want to use immunocompromised mice is to include the effect of immune system, right?
Following articles may be of interest in case you would still want to use human tumor cells.
I am not sure that I understand well your info exchanges.
For me:
1) no, you cannot use human cancer cells in "normal mice", because of immunogenic attacks from the mouse to the human cancer cells. As Tine said, if you are using immunodepressants, you will completely modify the biology of the human cancer cells.
2) "nude" or "athypic" mice are only immunocompromized, not actually immunodeficient.
3) if you want actually immunodeficient mice, you must use SCID mice, a model in which you can have mouse cancer cells in a mouse setting, without the mouse immune system.
Thus, I think that I do not well understand Ivane's question.
Immunodeficient mice are a necessity for xenograft experiments, as functional murine immune systems will lead to effects that are not comparable with the human microenvironment. When we do xenografts commercially (http://altogenlabs.com/xenograft-models/) we use immunodeficient mice, but if you don't have already immunodeficient ones, then cyclosporin treatment can help suppress the immune response.