The latest WHO guideline of CNS
tumor defined a RELA fusion-positive
ependymoma type with extremely poor prognosis, and the expression of
L1CAM was correlated well with the presence of RELA fusion. However, the
L1CAM protein expression in large sample
gliomas other than
ependymoma, its relationship with the RELA gene and its prognostic significance remained unknown. We examined the expression of
L1CAM in 565
glioma cases (WHO grade I-IV). The
L1CAM IHC-positive cases were selected to test RELA fusion with FISH break-apart probes.
L1CAM was positive in 109 cases (19.29%) of all 565
glioma cases, with 18.27% in low-grade
gliomas and 19.84% in high-grade
gliomas, respectively. Unlike
ependymoma,
L1CAM protein expression was not correlated with the C11orf95-RELA fusion gene in other
gliomas, but it had correction with the patient age (older than 45-year-old, p = 0.006), ATRX mutation (p = 0.003) and Ki67 (p = 0.007). High expression of
L1CAM was an independent prognostic factor in our cohort. Further analysis demonstrated that
L1CAM strong positive expression was significantly associated with poor prognosis in
gliomas, both in our cohort (p < 0.001) and TCGA (p < 0.009) dataset. Although uncorrelated with C11orf95-RELA fusion,
L1CAM was a significant poor prognostic marker in
glioma patients. More aggressive treatment should be taken for these patients and
L1CAM might be a promising therapeutic target in
glioma.