PCNA, Ki-67 and hTERT in residual benign meningiomas

Abstract

Background: Relapse in individual patients after incomplete/residual removal of meningiomas cannot be predicted by histology alone as re-growth occurs even in histologically benign meningiomas.

Materials and methods: Proliferating cell nuclear antigen (PCNA), Ki-67 and human telomerase reverse transcriptase (hTERT) labelling indices were measured in histological sections derived from residual meningiomas in 37 patients to assess their relationship to relapse. The labelling index (LI) expressed the percentage of tumour cell nuclei immunoreactive for PCNA, Ki-67 or hTERT in 1,000 tumour cells counted per section. The histological specimens comprised the following 2 groups: (i) stable for at least 10 years after initial partial resection of residual meningiomas: 20 specimens; (ii) relapsing between 11 and 145 months after initial resection of residual meningiomas: 17 specimens.

Results: The proliferative activity and hTERT expression do not directly correlate with every relapse. The PCNA LI significantly differed in the relapsing group (10.8%) compared to the stable group (5.5%) (p=0.08). The Ki-67 LI also was higher in the relapsing group (2.5%) than in the stable group (2.0%), but not statistically significantly (p=0.9). hTERT LI was significantly higher in the relapsing group (27.8%) than in the stable group (7.2%) (p<0.01).

Conclusion: The mean PCNA, Ki-67 and hTERT LI were higher in the relapsing group of residual meningiomas than in the stable group, although no statistical difference was found for PCNA and Ki-67. On the other hand, a statistical difference between the two groups of meningiomas was found for hTERT; however, it is no absolute predictor for relapse at the individual patient level.