The already-inflamed baseline state of Brca2−/− tumours (Cxcl10high, more T cells) and the reduced expression of PD-1 both help to explain why similar expression levels of Cxcl9 as in the Brca2WT tumours did not cause a significant survival benefit in the Brca2−/− tumours. This evidence concerns the gene CXCL9 and neoplasm.