By flow cytometry one day later, they found when co-cultured with 90Y-NM600-treated tumor cells, live CD4 and CD8 cells number and the expression of IFN-γ of CD8+ T cells increased, at the same time, CTLA-4 on T cells, an inhibitory immune signal, also increased compared to those co-cultured with untreated control tumor cells. Here, CTLA4 is linked to neoplasm.