A Study Of MUC1 In Multiple Myeloma And B-Non-Hodgkin's Lymphoma

Background and ObjectiveMultiple myeloma and Lymphoma are two hematological malignancies. Multiple myeloma produces monoclonal M protein by malignant plasma cells. Because plasma cells that are clonal proliferation can infiltrate bone and soft tissue, they cause the damage of bone, anaemia and kidney failure. However, sometimes the symptoms are not typical and the diagnosis becomes difficult in this situation. So far, MM is still considered incurable. MM accounts for 10% of the hematological malignancies, and it is the second most common hematological malignancy after Non-Hodgkins lymphoma. Lymphoma is a lymphoid tissue malignancy and divided into two broad categories by clinical and pathological feature: Hodgkin' s lymphoma (HL) and Non-Hodgkin' s lymphoma (NHL). NHL is a heterogeneous group of diseases and divided into B-cell and T-cell type. Different histological types have different clinical features and prognosis.MUC1 normally expresses in the luminal cavity of the epithelial tissues and organs, such as breast, pancreas and ovary, etc. Recently many studies have found that MUC1 is a highly glycosylated transmembrane glycoprotein that is abundantly overexpressed on the cell surface of many human adenocarcinomas like breast and ovarian cancers. As a tumor-associated antigen (TAA), MUC1 can be recognized by specific T cell, which has been recently studied in the aspects of diagnosis, prognosis and immune treatment in hematological diseases. There is no expression of MUC1 in normal resting T cells, spleen and tonsillar B cells, CD34+ stem cells, peripherical blood cells (red blood cells, platelets, granulocyte and monocyte)^[1] . Usually normal plasma cells do not express MUC1, but some studies found that plasma cells in patients with MM express MUC1 protein^[2] . In one of these articles, MUC1 expressed about 92% in the patients with MM^[3] . Some studies showed that the expression rate of MUC1 was very high in lymphoma, for example existed in all the ALCLs(anaplastic large cell lymphoma), 75% in HL, 75% in plasmacytoma and 50% in T-cell lymphoma^[4] . Huang^[5] detected 96 cases of peripherial T-cell lymphoma by immunohistochemistry and found that the positive rate of MUC1 was 58．3%. He also found that high expression of MUC1 was correlation with stageⅢ/Ⅳand extranodal disease≥2(P<0．05) . Complete remission (CR) and survive rate of the patients with positive and high expression MUC1 were less than the patients with negative and low expression of MUC1．Serum MUC1(sMUC1) appears to represent a truncated form of MUC1 that lacks the cytoplasmic domain of membrance bound, full-length MUC1^[6] . Its role in multiple myeloma and B-cell lymphoma have not been reported so far. In these studies we did MUC1 was highly expressed in the bone marrow of the patients with MM and lymphoma^[7,8] . On the basis of these preliminary researches, this study is to evaluate the clinical value of serum MUC1 in the patients with multiple myeloma and MUC1 in lymphoma.Methods(1) The method of enzyme linked immunosorbent assay (ELISA) was used to compare the sMUC1 levels in the 12 cases of new diagnosed multiple myeloma, 15 cases of post-chemotherapy and 46 healthy donors.(2) The expression of MUC1 in B-NHL was detected by SP immunohistochemistry.Results(1) The mean concentration of sMUC1 in the new diagnosed patients with multiple myeloma was 33．44U/ml (10．86-88．80U/ml). In the patients of post-chemotherapy the mean concentration was 11．6U/ml (3．92-22．22 U/ml), and in the healthy donors the concentration was 12．81U/ml (3．84-30．45 U/ml). The level of sMUC1 in the new diagnosed patients was significantly higher than the patients of post-chemotherapy (P=0．001) and healthy donors (P=0．000) . There was no significant difference between post-chemotherapy and healthy donors (P＝0．461) . An analysis of correlation between the expression of MUC1 and other clinic parameters showed that increased sMUC1 expression was not significantly associated with immunoglobulin, globulin, plasma cells, age, and haemoglobin.(2) The positive expression of MUC1 was in 9 of 27 B-NHL patients (33．3%). The level of MUC1 in the B-NHL patients was not significantly higher than the control (P>0．05) . There was not significant difference in various pathological types of B-NHL patients (P>0．05) .Conclusions(1) Our study show that sMUC1 may be one of the tumor markers for the diagnosis of multiple myeloma. Serum MUC1 can also be used as one of the indicators of prognosis and the observation of the chemotherapy efficacy.(2) The positive expression of MUC1 is observed in some patients of B-NHL. The expression level and significance of MUC1 are still to be explored.