A Comparative Study on MIB-1, AgNORs and PCNA Expressions in Astrocytic Tumors

Choi, Yang Moon; Kim, Tae Young; Yoon, Ki Jung; Moon, Hyung Bae; Kim, Jong Moon

Abstract

Cell cycle associated nuclear proteins such as proliferating cell nuclear antigen(PCNA), argyrophilic nucleolar organizer regions(AgNORs) and the family of nuclear proteins identified by the Ki-67 epitope, have been primarily utilized for estimating of growth potential of neoplasms. Although PCNA and AgNORs staining are possible in the paraffin-embedded tissue, Ki-67 staining had been only possible on frozen sections. Recently monoclonal antibody MIB-1 is available, and reacts with the Ki-67 epitope in paraffin-embedded tissue. Twenty eight astrocytic tumors in paraffin-embedded, archival materials were stained by immunohistochemical technique for the MIB-1, PCNA, and by silver colloid stain for AgNORs. The MIB-1 labeling indicies(LI) ranged from 2 to 25%(10+/-7.58) for 10 glioblastomas; from 2 to 15%(7+/-3.74) for 11 anaplastic astrocytomas; and from 1 to 5%(3+/-1.91) for low grade astrocytomas. Glioblastomas and anaplastic astrocytomas exhibited significantly higher MIB-1 LI than their benign counterparts(p<0.05). The AgNORs count per cell ranged from 1.3 to 3.1(1.96+/-0.57) for 10 glioblastomas: from 1.2 to 3.1(1.9+/-0.64) for 11 anaplastic astrocytomas: and from 0.8 to 1.5(1.2+/-0.26) for low grade astrocytomas. Glioblastomas and anaplastic astrocytomas exhibited significantly higher AgNORs count than their benign counterparts(p<0.05). The PCNA LI ranged from 10 to 40%(24.5+/-10.39) for 10 glioblastomas; from 5 to 20%(11.6+/-5.24) for 11 anaplastic astrocytomas; and from 5 to 10%(7.1+/-2.67) for low grade astrocytomas. The differences of PCNA LI between glioblastomas and anaplastic astrocytomas(p<0.01), and between glioblastomas and low grade astrocytomas(p<0. 001) were statistically significant. Linear regression analysis showed correlations between MIB-1 LI and AgNORs count(Spearmans r=0.4306, p<0.05), between PCNA LI and AgNORs count(Spearman's r=0.586, p<0.05) and between PCNA and MIB-1 LI(Spearman's r=0.4523, p<0.05). These findings suggest that LI of MIB-1, PCNA and AgNORs count are correlated each other, and can be used as helpful markers for differentiating astrocytic tumors in addition to conventional staining methods.