The prognostic role of MYC has been well documented in non-central nervous system
diffuse large B-cell lymphoma; however, it remains controversial in central nervous system
diffuse large B-cell lymphoma. To investigate the prognostic value of MYC, we analyzed the MYC
protein expression by immunohistochemistry,
mRNA expression by
RNA in situ hybridization, and gene status by fluorescence in situ hybridization in 74 cases of central nervous system
diffuse large B-cell lymphoma. Moreover, we examined the correlation between MYC translocation,
mRNA expression, and
protein expression. The mean percentage of MYC immunopositive cells was 49%. Using a 44% cutoff value, 49 (66%) cases showed MYC
protein overexpression. The result of
mRNA in situ hybridization using the
RNA scope technology was obtained using the H-scoring system; the median value was 34.2. Using the cutoff value of 63.5, 16 (22%) cases showed MYC
mRNA overexpression. MYC gene rearrangement was detected in five out of 68 (7%) cases. MYC translocation showed no statistically significant correlation with
mRNA expression; however, all MYC translocation-positive cases showed MYC
protein overexpression, with a higher mean percentage of MYC
protein expression than that of translocation-negative cases (78 vs 48%, P=0.001). The level of MYC
mRNA expression was moderately correlated with the level of MYC
protein expression (P<0.001). The mean percentage of MYC
protein expression in the high MYC
mRNA group was higher than that in the low MYC
mRNA group (70 vs 47%, P<0.001). A univariate analysis showed that age over 60 years, Eastern Cooperative Oncology Group (ECOG) performance status ≥2 and MYC
protein overexpression were significantly associated with an increased risk of death. MYC translocation and MYC
mRNA expression had no prognostic significance. On multivariate analysis, MYC
protein overexpression and ECOG score retained prognostic significance.