چكيده لاتين :
BACKGROUND: Astrocytic tumors are the most common primary tumors of the central nervous system. These tumors
have an inherited tendency to progress and recurrence. The histopathological examination and grading do not always
identify the subset of these tumors especially when the tumor sample is small or inadequate. This study was undertaken
to answer the question whether MIB-I expression could assist in discrimination between low grade and high-grade
glioma and gliosis especially when the biopsy sample is small, such as in stereotactic brain biopsy.
Methods: This descriptive analytical study was performed on 114 glial and gliotic paraffin-embedded tissues. KI67 immunohistochemistry
was also used on paraffin section using the monoclonal antibody MIB-l. The results were analyzed
by ANOVA test.
Results: Based on light microscopic findings 89 (78.07%) were astrocytomas and 25 (21.9%) were reactive gliosis. The
mean Ki67 labeling index (LI) was 25.2% ((PLUS-MINUS)30) for astrocytomas in general and 1.92 ((PLUS-MINUS)1.2) for gliosis. In other words,
it was 1.8 ((PLUS-MINUS)I) for grade I, 14.5% ((PLUS-MINUS)4) grade II and 64.5 % (±19.3) for grade IIIIIV astrocytomas. The MIB-l labeling
index for astrocytic tumors was significantly higher than that for gliosis (P(LESS THAN)O.OO I) and it increased with increasing tumor
grade. However, MIB-I labeling index was the same for pilocytic astrocytoma and gliosis so there was no meaningful
difference between grade I astrocytoma and gliosis.
CONCLUSIONS: Given the conventional microscopic examination and KI67 (MIB-I) method for grading astrocytomas,
MIB-I is more reliable and a complementary method for definitive diagnosis.
