Previous studies have shown that certain tumour cells are able to produce tumour-specific immunoglobulins. These immunoglobulins differ in size from those produced by B lymphocytes and are capable of aberrant assembly. They also appear to play a role in tumour growth and cell proliferation. In the case of glioblastoma, the most common primary tumour of the central nervous system, transcriptomic studies using RNAseq study demonstrated the expression of immunoglobulins by the tumour. To identified at the protein level of these immunoglobulins, Western blots were performed under non-reducing conditions on protein extracts from the cells and secretome of glioblastoma cell lines, allowing the identification of different immunoglobulin assemblies found intracellularly and a complete form found extracellularly. The different conditions were also tested under reducing conditions, allowing us to study the different chains that make up these immunoglobulins. Proteomic analyses of the identified bands were confirmed their identity. As glioblastoma tumours are subject to cellular stress due to hypoxia and limited nutrient supply, the effect of stress on immunoglobulin production was also tested by starving cell cultures. This showed that stress stimulates immunoglobulin production. Taken together, this work has enabled us to better characterise the immunoglobulins produced by glioblastoma cells and to hypothesise the function of these immunoglobulins.