Nuclear expression of β-catenin and stem cell markers as potential prognostic indicators in medulloblastoma

To study the prognostic role of β-catenin and stem cell markers in medulloblastoma (MB).

Sixty cases of MB were retrospectively analyzed to study the expression of β-catenin, CD15, and CD133 by immunohistochemistry. Their expression was correlated with histological subtypes and event-free survival (EFS). Patients were divided into Group 1 and 2 based on non-occurrence and occurrence of events during the follow-up period.

Fifty of the 60 cases were of classic type of MB while nine were of desmoplastic subtype and one case showed chondroid and rhabdomyoblastic differentiation. Immunoreactivity for β-catenin was observed as nuclear and/or cytoplasmic positivity within the tumor cells. Forty-one (68.3%) cases showed cytoplasmic positivity, while nuclear positivity was seen in 21 (35%) cases. There was a significant correlation between nuclear expression of β-catenin and different histological subtypes by Chi-square test (P value<0.05). A statistically significant positive correlation of β-catenin nuclear positivity with EFS was observed. Among 60 cases, 37 cases (67.3%) showed presence of CD15+ tumor cells with percentage of positivity varying between 0.1 to 17.1%. Overall, 42 of 60 (70%) cases showed presence of CD133+ cells. The percentage of positivity varied between 0.1 to 16.5%. A statistically significant negative correlation of CD15 and CD133 positivity with EFS was observed.

Nucleopositive β-catenin cases were associated with a favorable outcome on univariate analysis. Both CD15 and CD133 positivity were associated with a worse outcome on univariate analysis.