The expression of cell adhesion molecule L1 has been identified in a vast spectrum of tumors; however, its expression pattern with regard to tumor type is rarely discussed. In the present study, we studied L1 levels in human glioblastomas and neuroblastomas, and compared the expression and secretion of L1 in human glioblastoma U87-MG and neuroblastoma SK-N-SH cells. Immunofluorescence staining revealed different grades of L1 staining in human glioblastoma and neuroblastoma samples. In U87-MG cells, full-length L1 was weakly detected in cell lysates (CLs), while greater levels of abundant soluble L1 were confined in conditioned culture medium (CCM). In contrast, higher levels of full-length L1 were confined in SK-N-SH CLs, while almost no soluble forms of L1 were detected in CCM. Our data indicates various expression patterns of L1 in U87-MG and SK-N-SH cells, which may underlie the different malignancies of the two neural tumor types and further stress the importance of soluble L1-mediated signaling pathways in cell malignancy.