NLGN1 and colorectal cancer: There have been reports that high expression of CD99 in tumors is involved in the infiltration of immunosuppressive macrophages, in addition to the malignant transformation of tumor cells themselves [26, 27], and some study reported that high expression of NLGN1 was a poor prognostic factor in colorectal cancer, prostate cancer, and pancreatic cancer [28, 29].