ICOSLG and neoplasm: The induction of ICOSL expression, however, was significantly lower in most of the murine syngeneic tumour cell lines tested, including B16-F10 melanoma, MC38 and CT26 colon carcinoma, TRAMP C2 prostate carcinoma, ID8 ovarian carcinoma, 4T1 breast carcinoma, and MB49 bladder carcinoma (Fig. 2c).