Tumor cell-intrinsic expression of BTLA, ICOS and TIGIT in human breast cancer.

We recently described primary tumor expression of BTLA (B and T lymphocyte associated), ICOS (inducible T-cell costimulator) and TIGIT (T-cell immunoreceptor with Ig and ITIM domains) in the tumors of patients with breast cancer (1-3), but expression of CD28/CTLA4 family receptors (4, 5) by cells of the tumor rather than by tumor-infiltrating immune cells is not well understood. We used published (6) whole transcriptome data from laser capture microdissection-isolated tumor cells (rather than bulk tumor) and describe primary tumor cell-intrinsic expression of BTLA, ICOS and TIGIT in patients with triple negative breast cancer.