In part, the paucity of information reflects thedifficulties of working with global COX-2 knock out mice, which have breeding problems,severe renal pathology and a shortened life span [39], none of which are encountered in our targeted COX-2MECKO mice, aswell as the extensive use of immune deficient host mice for tumor transplant studies.Compared to WT, three populations of immune cells - CD3+CD4+,which are Th lymphocytes, CD3+CD8+ cells, which areCTLs and CD3-CD8+, which encompass NKs and dendritic cells - wereelevated in COX-2MECKO tumors. This evidence concerns the gene CD4 and neoplasm.