Combination of BCL-2 and MYC protein expression improves high-risk stratification in diffuse large B-cell lymphoma

PURPOSE To evaluate whether the addition of two biological markers (MYC and BCL-2 protein overexpression) improves the stratification of high-risk patients with diffuse large B-cell lymphoma (DLBCL). METHOD Seven risk factors were identified at diagnosis, and a maximum of 7 points were assigned to each patient. The patients were classified according to four risk groups: low (0-1), low-intermediate (2-3), high-intermediate (4), and high (5-7). Only high-risk patients with DLBCL were included in this analysis. We retrospectively examined 20 cases from 2008 to 2013 at the Nanjing Drum Tower Hospital. RESULTS The median expression of MYC protein was 60%, and 17 of 20 (65%) evaluable cases overexpressed MYC. The median expression of BCL-2 protein was also 60%. Eighteen of 20 (90%) evaluable cases showed BCL-2 overexpression. Additionally, 12 out of 20 cases (60%) demonstrated coexpression of MYC and BCL-2 proteins. The percentages of overall survival and progression-free survival at the median follow-up time (36 months) were 33.3%±16.1% and 16.9%±13.5%, respectively. By comparison, nine, four, and 20 patients were classified as high risk based on the International Prognostic Index (IPI), National Comprehensive Cancer Network(NCCN)-IPI, and revised IPI criteria, respectively. According to the IPI and NCCN-IPI stratification, the risk groups demonstrated closely overlapping survival curves. In addition, four out of 20 cases were identified as low-intermediate risk according to the NCCN-IPI criteria. CONCLUSION The addition of MYC and BCL-2 protein expression to the IPI could identify a subset of DLBCL patients with high-risk clinicopathological characteristics and poor clinical outcome.