The prognostic value of S-100 protein and Ki-67 index in olfactory neuroblastoma

Our study evaluated the prognostic value of S-100 protein and Ki-67 labeling index in 85 patients with olfactory neuroblastomas, and our results suggested that they were reliable prognostic factors. Objective To evaluate the prognostic value of S-100 protein and Ki-67 labeling index in olfactory neuroblastomas. Methods A retrospective study was conducted on a cohort of 85 patients with olfactory neuroblastomas. The immunohistochemical expression of S-100 and Ki-67 was assessed, and the predictive value of S-100 and Ki-67 was further evaluated. The optimal cutoff value of Ki-67 labeling index was determined using time-dependent receiver operating characteristic curve analysis. Overall survival and progression-free survival were assessed using the Kaplan-Meier method. Results A cut-off Ki-67 labeling index value of 67.5% was determined for prognosis in patients with olfactory neuroblastomas. There was a significant correlation between Ki-67 expression and cervical lymph node metastasis (P = 0.049). Compared with S-100 (+), S-100 (-) was associated with a higher rate of lymph node metastasis and a higher level of Ki-67 (P = 0.007, < 0.001, respectively), as well as an advanced Kadish stage (P = 0.037). Survival analyses showed that patients with S-100 (+) had better 5-year overall survival than those with S-100 (-) (P = 0.028), and patients with both S-100 (+) and Ki-67 (<67.5%) had superior 5-year overall survival compared with all the other patients (P = 0.0225). Conclusion Our findings suggest that S-100 combined with Ki-67 labeling index are reliable prognostic factors in patients with olfactory neuroblastomas.