Tumors need less regulation

Efforts to induce anti-tumor immunity have so far proven disappointing. Now, Tyler Curiel, Weiping Zou (Tulane University, New Orleans, LA), and colleagues suggest that greater success may come if clinicians first disable regulatory T (T_reg) cells. These cells, say the group, are recruited by human tumors to damp down any immune response against tumor cells.

T_reg cells have been studied primarily for their ability to turn off immune responses during organ transplantation or autoimmune disease. Preliminary results in mice suggested that depletion of T_reg cells might improve tumor prognosis, although these experiments may have depleted other cell types.

Now, Zou's team finds that human malignant ovarian cancers contain substantial numbers of T_reg cells, with more T_reg cells present at later tumor stages. The patients...