A substantial fraction of the T cell pool is constitutively resident within the skin, but the role of these cells remains poorly understood. In October 19 Science Michael Girardi and colleagues from Yale School of Medicine show that gamma-delta (γδ) T cells in the skin use evolutionarily conserved proteins in the defense against skin cancer development.

Girardi et al. found that mice lacking γδ T cells are highly susceptible to skin cancer induced by either inoculation of carcinoma cells or by chemical carcinogenesis. In addition, they found that the anti-cancer function of the γδ T cells relies on the expression of NKG2d — a receptor for Rae-1 on the tumor cells (Science 2001, 294:605-609).

"These findings are clearly relevant to understanding the selective pressures on developing tumors and to considering the types of immune responses that would be useful in clinical intervention" said the authors.