Prognostic Value of Differential Expression of Polymerase Eta Gene in Nonresponding Patients With Diffuse Large B-cell Lymphoma

Abstract

Diffuse large B-cell lymphoma (DLBCL) represents the most common subtype of non-Hodgkins lymphoma. After the introduction of rituximab therapy like rituximab, cyclophosphamide, doxorubicin vincristine, prednisolone, there has been considerable improvement in the 5-year overall survival in this group of patients, but the nonresponding patients are a challenge to the clinician. The translesion polymerases are unique polymerases that make cells tolerant to DNA damage. Many point mutations are introduced owing to their inherent property of bypassing the points of lesions, preventing the cell from stalling replication. However, the impaired activity of these polymerases can lead to the development of tumors with aggressive clinical course. In this study, the gene expression levels of polymerase eta (POLE) were compared in 2 cohorts of patients with DLBCL: the first cohort, patients who had achieved complete response, and the second cohort, patients who were refractory to the treatment or had relapse within 2 years of treatment. There was a significantly upregulated expression in the refractory/relapse cohort compared with the complete remission cohort (P = 0.0001). The high POLE expression levels correlated significantly with advanced disease stages (III and IV) and poor disease-free survival in the Kaplan-Meier curve. The high POLE expression levels were correlated with poor disease-free survival in nonresponder patients with DLBCL. The results concluded that patients with DLBCL with a high polymerase gene expression may show nonresponsiveness to chemotherapy; hence the functional impact of upregulated expression of POLE in DLBCL requires an in-depth assessment.