Immunohistochemical overexpression of BCL-2 protein predicts an inferior survival in patients with primary central nervous system diffuse large B-cell lymphoma

This study was designed to analyze the clinical characteristics and prognostic value of c-MYC and BCL-2 proteins expression in patients with primary central nervous system diffuse large B-cell lymphoma (PCNS-DLBCL). 82 patients newly diagnosed with PCNS-DLBCL, from January 2008 to November 2018, were enrolled in this study. Clinical characteristics, immunohistochemical features, laboratory examinations, and treatment outcome were analyzed among these patients. Among these 82 cases, 45 were males (54.9%) and 37 were females (45.1%). Age ranged from 16 to 78 years old, and 29 patients (35.4%) were elder than 60 years old, with median age at 57 years old. According to Hans classification, 25 were accounted for origin of germinal center B-cell (GCB) subtype (30.5%) and 49 were accounted for non-GCB subtype (59.8%), respectively. Eight patients were unclassified due to lack of detailed pathological results. The median survival of these 82 patients was 30 months, and 1-year, 3-year, and 5-year overall survival (OS) rate was 59.7%, 44.6%, and 34.1%, respectively. Patients treated with sequential HD-MTX based chemotherapies showed a superior prognosis than those without. In combination with rituximab, the outcome was further improved. The median OS was 55 months in HD-MTX + R group, 27 months in HD-MTX group, and 9 months in other groups, respectively. Univariate analysis identified age ≥60, ECOG score ≥ 2 points, and overexpression of BCL-2 protein (≥85%) were adverse prognostic factors for OS. Co-expression of c-MYC (≥40%) and BCL-2 (≥50%) proteins was associated with poor ECOG score, high Ki-67 expression, and trended towards an inferior outcome. Gender, lesion location, number of lesions, lactic dehydrogenase (LDH), cell of origin, BCL-6 protein expression, expression of c-MYC protein alone and Ki-67 ≥85% had no significant impact on OS. In patients with PCNS-DLBCL, age ≥60 years old, ECOG score ≥2 points, and overexpression of BCL-2 protein (≥85%) were associated with a poor survival. HD-MTX based chemotherapies in combination with rituximab could improve the prognosis.