The ability to concentrate iodide as a marker of hormone dependence in GR mouse mammary tumors.

We have previously shown that hormone-dependent (HD) but not hormone-independent (HI) mammary tumors of GR mice concentrate iodide. Since hormone dependence is lost during serial transplantation of the tumors, we have investigated whether the ability to concentrate iodide is lost simultaneously. All tumors progressing to hormone independence lost the ability to concentrate iodide at the time of transition from the HD to the HI state. We believe, therefore, that the ability to concentrate iodide is a marker of hormone dependence in GR mouse mammary tumors.