OBJECTIVETo study the expression of β-catenin protein and the status of loss of heterozygosity (LOH) on chromsome 10q in medulloblastoma, with clinical correlation.

METHODSImmunohistochemical study for β-catenin protein was carried out in 50 cases of medulloblastoma encountered in the First Affiliated Hospital of Xinjiang Medical University during the period from 2002 to 2011, including 32 cases of classic medulloblastoma, 13 cases of desmoplastic medulloblastoma and 5 cases of medulloblastoma with extensive nodularity. The status of LOH on 10q was also detected by fluorescence in-situ hybridization. The clinicopathologic characteristics and prognostic parameters were studied by Kaplan-Meien and Cox analysis.

RESULTSThe rates of expression of β-catenin protein in classic medulloblastoma, desmoplastic medulloblastoma and medulloblastoma with extensive nodularity were 53.1% (17/32), 4/13 and 1/5, respectively. The rate of LOH on 10q was 33.3% (8/24) in classic medulloblastoma and 2/11 in desmoplastic medulloblastoma. There was no statistically significant difference between the two tumor types. Univariate analysis showed that the expression of β-catenin protein (P = 0.022), lack of LOH on 10q (P = 0.020), extensiveness of tumor resection (P < 0.01), radiotherapy (P = 0.002) and chemotherapy (P < 0.01) represented important prognostic factors.

CONCLUSIONSMedulloblastoma with expression of β-catenin protein and without LOH on 10q carries a better prognosis. Assessment of these parameters is helpful in evaluating prognosis and subsequent patient management.