Staining for kappa light chain identifies human tumor cells in contralateral bone fragments of a mouse injected with soluble syndecan-1–expressing cells.

To determine if tumor cells had disseminated from the bone that was injected with tumor, the noninjected contralateral bone was harvested at the time of animal killing and processed for immunohistochemistry by using anti-kappa light chain antibodies. Stained tumor cells are clearly localized within the bone at both (A) low (× 200) and (B) high (× 400) magnification.