Germline ALK variations are associated with a poor prognosis in glioma and IDH -wildtype glioblastoma

Background Glioma is the most common primary brain tumor. Clear classification is crucial for accurate diagnosis and individualized treatment. Histopathological characteristics and genetic alterations have shown to be related to prognosis and treatment response. Germline variants are important components of genetic alterations. However, the distribution of germline variations in glioma patients and their association with survival remain unknown. Methods We carried out whole-exome sequencing on 99 cases to explore germline variants in glioma. We also analyzed the association of germline variants with clinicopathological features and other prognostic indicators. Results All the glioma cases harbored rare germline variants. Germline ALK variants ( gALK -Mut) were identified in 12/99 (12.12%) patients. The g ALK -Mut patients had significantly shorter overall survival than germline ALK wildtype (g ALK -WT) patients in the all glioma group (99 cases) and the subset of patients with IDH -wildtype glioblastoma ( IDH -WT-GBM, 39 cases) ( P = 0.013 and 0.027, respectively). The gALK -Mut patients also had higher frequency of BIRC5, PIK3CA and RPN1 somatic mutations than the g ALK -WT patients in IDH -WT-GBM. Other confounding factors appeared to contribute to patient survival. The subgroup of patients in IDH-WT-GBM with g ALK -Mut/ TP53 -Mut had worse prognosis than the g ALK -WT/ TP53 -Mut subgroup ( P = 0.031); The g ALK -Mut /TERT- WT and g ALK -Mut /TER T-Mut subgroups both had a worse prognosis than the g ALK- WT /TERT- Mut subgroup ( P = 0.031 and 0.018, respectively). Conclusions Our study revealed ALK variation was an independent indicator of poor prognosis in glioma and IDH -WT-GBM. It could be a promising biomarker and tractable therapeutic target for this deadly disease.