Immunohistochemical profile and prognostic significance in primary central nervous system lymphoma: Analysis of 89 cases

Abstract

The majority of primary central nervous system lymphomas (PCNSLs) are diffuse large B cell lymphoma, characterized by poor prognosis. In the present study, the expression of cluster of differentiation (CD)10, B cell lymphoma (BCL)-6, multiple myeloma-1 (MUM-1), BCL-2, CD138 and Ki-67 was analyzed by immunohistochemistry in 89 Chinese PCNSL cases, and the potential prognostic significance was evaluated. CD10, BCL-6, MUM-1, BCL-2 and CD138 were positive in 16.9 (15/89), 51.7 (46/89), 92.1 (82/89), 73.3 (63/86) and 0% (0/65) of all cases, respectively. According to the Hans algorithm, 71 patients (79.8%) were classified into the non-germinal center B cell-like (non-GCB) group, indicating a post-germinal center origin of PCNSL. The median follow-up time of 73 patients was 13 months [95% confidence interval (CI), 10.93-15.08]. The median overall survival (OS) time was 45.3 months (95% CI, 25.01-65.59) and the median progression-free survival (PFS) time was 30.0 months (95% CI, 13.43-46.57). Age (>60 years) was associated with a shorter OS time (P=0.009). Ki-67 (cutoff point 90%) was associated with shorter OS (P=0.037) and shorter PFS (P=0.039) times. No other immunohistochemical markers were associated with prognosis. On multivariate analysis, age (>60 years) was associated with shorter OS time (P=0.038), but immunophenotype and expression status of Ki-67, CD10, BCL-6 and BCL-2 did not predict prognosis. In conclusion, high Ki-67 expression may predict poor prognosis in PCNSL. The present study was limited by its sample size and short follow-up time. This requires more evidence to further clinical study.

Keywords: Ki-67; diffuse large B cell lymphoma; germinal center B cell-like; non-germinal center B cell-like; primary central nervous system lymphoma.

Figure 1.

Immunohistochemical labeling. (A and B) H&E staining. In tumor cells with the diffuse distribution, the size of nuclei were 2 times greater than of normal lymphocytes. (A) Magnification, ×200. (B) Magnification, ×400. (C) CD20 cell membrane staining performed using the EnVision method. Magnification, ×200. (D) CD10 cell membrane staining performed using the EnVision method. Magnification, ×200. (E) BCL-6, nuclei staining, EnVision method, ×100. (F) MUM-1 nuclei staining performed using the EnVision method. Magnification, ×200. (G) BCL-2 cytoplasmic staining performed using the EnVision method. Magnification, ×200. (H) Ki-67 nuclei staining performed using the EnVision method. Magnification, ×200. H&E, hematoxylin and eosin; CD, cluster of differentiation; BCL, B cell lymphoma; MUM-1, multiple myeloma-1.

Figure 2.

Comparison of OS and PFS time between age >60 and age ≤60 years by log-rank test. Univariate analysis revealed that younger age (≤60 years) was associated with a longer OS time (P=0.009) compared with older age (>60 years). No significant difference was observed for PFS time (P=0.141). OS, overall survival; PFS, progression-free survival.

Figure 3.

Comparison of OS and PFS time between Ki-67 expression >90 and ≤90% by log-rank test. Univariate analysis revealed that high expression of Ki-67 (>90%) was associated with a shorter OS (P=0.037) and PFS (P=0.039) times compared with low expression of Ki-67 (≤90%). OS, overall survival; PFS, progression-free survival.