Ki-67 immunostaining in astrocytomas: Association with histopathological grade - A South Indian study.
BACKGROUND
Astrocytomas are the most common primary tumor of the central nervous system. The distinction between different tumor grades can be tested despite criteria given by the World Health Organization (WHO). Ki-67 is a potent biological marker used in grading of astrocytomas, which estimates growth of the neoplasm quantitatively and will help in predicting prognosis accurately.


OBJECTIVE
The aim of this was to study the proliferative activity using Ki-67 immunostaining and to assess the relationship of Ki-67 staining with the histopathological grading of astrocytomas.


METHODS
Thirty cases of histologically proven astrocytomas were studied. The histopathological grade was assessed using the 2007 WHO criteria. Immunohistochemistry for Ki-67 was done on paraffin-embedded wax sections.P< 0.05 was considered statistically significant.


RESULTS
Thirty cases of astrocytomas studied showed a male preponderance (M:F = 1.72:1) with a mean age of 48.1 years. Of these, Grade I, (n= 1, 3.33%), Grade II, (n= 7, 23.3%), Grade III (n= 6, 20%), and Grade IV (n= 16, 53.3%) astrocytomas were analyzed. The mean Ki-67 labeling index (LI) in Grades I, II, III, and IV was 0.02, 0.81, 9.14, and 17.81, respectively. Statistically significant difference was seen in the Ki-67 LI of low-grade (Grade II) and high-grade astrocytomas (Grades III and IV). There was concordance between histopathological grading and Ki-67 LI in 27 (90%) and discordance in 3 (10%) cases.


CONCLUSIONS
Ki-67 LI varies considerably in different grades of astrocytomas and considerable overlaps can be observed between them. It can be of great help in situations where there is a lack of correlation between clinical parameters and histopathological diagnosis. Determination of Ki-67 LI should constitute a part of routine investigations in patients with astrocytomas.
Department of Pathology, JSS Medical College, JSS University, Mysore, Karnataka, India.
Nandish Vastrad
NV
Shivaprasad
Department of Pathology, JSS Medical College, JSS University, Mysore, Karnataka, India.
Suchitha
S
Satish
Department of Pathology, JSS Medical College, JSS University, Mysore, Karnataka, India.
Sunila
S
Ravishankar
Department of Pathology, JSS Medical College, JSS University, Mysore, Karnataka, India.
Manjunath Gubbi
MG
Vimalambike
Astrocytomas; Ki-67 labeling index; histopathological grading
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