Expression of Non-B Lymphocyte Immunoglobulin G in Bladder Cancer and Its Biological Function

  Objective  The aim of this study was to investigate the expression of non-B lymphocyte immunoglobulin G(non B-IgG) in bladder cancer and its role in the biological behavior of cancerous cells.

  Methods  The expression of non B-IgG proteins in bladder cancer tissue of 89 cases (study group, aged 37-89 years, median age (68.0±4.3)) and normal bladder tissue of 7 cases(control group) was detected by immunohistochemistry. There were 47 cases of high histological grades, and 42 cases of low grades. The non B-IgG protein and mRNA in bladder cancer cell lines were detected by Western blot and RT-PCR, respectively. After knocking down the expression of IgG in bladder cancer cells, we investigated the migratory and invasive abilities of bladdercancer cells by Transwell and Matrigel assays.

  Results  The rate of positive expression of non B-IgG in bladder cancertissues was higher than that in normal tissues; and the expression of IgG was correlated with tumor size, histological grade and reoccurrence(P < 0.05). However, the expression of non B-IgG had no relation with age, sex, and tumor number(P>0.05). Western blot and RT-PCR results also showed that nonB-IgG was expressed in bladder cancer cells. After knocking down IgG expression, the ability of migration and invasion of bladder cancer cells was inhibited.

  Conclusions  Non B-IgG was over-expressed in bladder cancer tissues, promoting migration and invasion of cancer cells, which indicated that IgG might be a potential therapeutic target of bladder cancer.