Expression of Twist 1 in bone marrow and extramedullary lesions of patients with myeloma and its prognostic significance

Abstract

In patients with multiple myeloma (MM) extramedullary (EM) lesions could be a possible indicator of poor prognosis. Twist 1, an EMT related transcription factor, is known to play an important role in embryonic development and also in the process of tumor cell proliferation, apoptosis, metastasis etc. The Twist 1 protein expression hence has prognostic significance in MM. This study investigates expression of Twist-1 in MM patients with extramedullary lesions and its relationship with clinicopathological data and prognosis, so as to elucidate the clinical significance of Twist-1 expression. Patients with MM complicated with EM lesions were selected retrospectively, including 35 cases in the bone marrow group (MM complicated with extramedullary lesions) and 80 cases in the extramedullary group (MM combined with extramedullary lesions). The expression of Twist 1 protein was detected by immunohistochemistry. The relationship between Twist 1 protein expression and general clinicopathological data was analyzed by statistics. The relationship between Twist 1 protein expression and prognosis was analyzed by COX single factor and multivariate regression analysis. Immunohistochemical staining showed that the expression level of Twist-1 protein in the nucleus of myeloma cells in the extramedullary group was significantly higher than that of the bone marrow group. However, in the cytoplasm of myeloma cells, there was no significant difference in the expression level of Twist-1 protein between the extramedullary group and the bone marrow group. The expression level of Twist-1 protein in extramedullary tissue was not related to sex, age, D-S stage, ISS stage, immunoglobulin type, creatinine and hemoglobin. The expression level of β2-microglobulin in Twist-1 high expression group was significantly higher than that of Twist-1 low expression group. Follow-up findings discovered that overall survival (OS) of Twist 1 high expression group was significantly lower than that of Twist 1 low expression group. COX multivariate analysis showed that Twist 1 protein and International Staging System (ISS) stage were independent risk factors affecting OS for 3 years. The high expression rate of Twist 1 protein in extramedullary lesions of MM patients with extramedullary lesions is significantly higher than that in bone marrow tissues of patients with extramedullary lesions. The results suggest that high expression of Twist 1 protein is an independent risk factor affecting the prognosis of MM patients with extramedullary lesions.