The results of Flow cytometric analysis showed that the proportion of CTLA4+ T cells in tumor tissues was significantly increased in the BCSCs-231 group compared with the MDA-MB-231 group, while the cytotoxicity of CD8+ T cells was suppressed; the proportion of CTLA4+ T cells in tumor tissues was significantly decreased in the BCSCs-231 + anti-CHI3L1 group compared with the BCSCs-231 group, while the cytotoxicity of CD8 T cells was suppressed in the BCSCs-231 group compared with the MDA-MB-231 group. Here, CTLA4 is linked to neoplasm.