Significance of myeloid antigen expression in precursor T lymphoblastic lymphoma

Precursor T lymphoblastic lymphoma (T-LBL) is a highly aggressive lymphoma. Myeloid antigen expression was found in some of the patients, and its clinical significance is worth studying. This study was to compare the clinical features, short-term efficacy and survival of T-LBL patients with or without myeloid antigen expression so as to evaluate its prognostic significance. Forty-five T-LBL patients, with a median age of 14 years, were treated at Sun Yet-sen University Cancer Center between January 2000 and July 2008. These patients were divided into myeloid antigen-positive group (My(+) group) and myeloid antigen-negative group (My(-) group) based on the flow cytometric (FCM) analysis in bone marrow or pleural fluid. Myeloid antigen expression and its correlation with the short-term efficacy and overall survival were assessed in the two groups. There were 18 patients (40.0%) in the My(+) group and 27 (60.0%) in the My(-) group. The myeloid antigen expression was negatively correlated with the initial level of lactate dehydrogenase (LDH), but not with other clinical features. The remission rate was lower in the My(+) group than in the My(-) group (38.8% vs. 70.3%, P = 0.028). The 2-year overall survival rate was lower in the My(+) group than in the My(-) group (51.9% vs. 78.7%, P = 0.036). By age subgroup analysis, there were no differences in response and survival rate among children and adolescents with or without myeloid antigen expression. But the remission rate and the 2-year overall survival rate were significantly lower in adult patients with myeloid antigen expression than in patients without it. Univariate and multivariate analysis demonstrated that age and myeloid antigen expression were adverse prognostic factors. Myeloid antigen expression is a predictor of a poor response to chemotherapy, and adverse prognostic factor in adult T-LBL, but not in children with T-LBL.