Table 1.

The Standard of Care Treatment of Glioblastoma and It’s Potential Impact on Immunotherapies.

Standard of Care	Potential Detrimental Factors	Potential Beneficial Factors
Surgery	• Limited antigenic tumor epitopes after extensive resection	• Surgically mediated cytoreduction leads to a smaller tumor burden for the immune system to address • May provide direct immune stimulation • May serve as a means of delivering local immunotherapies
Radiation	• May increase the likelihood of lymphopenia associated with temozolomide • May select for more aggressive tumor cell clones • May lead to increased tumor PD-L1 expression, IDO expression, and immunosuppressive macrophage infiltration	• May increase mutations within the tumor leading to the expression of more antigenic tumor epitopes • Radiation mediated cytoreduction leads to a smaller tumor burden for the immune system to address • May stimulate effector T cell infiltration into tumor
Temozolomide	• Contribute to leukopenia and particularly lymphopenia • May increase mutations within the tumor increasing its malignancy • May select for more aggressive tumor cell clones	• May cause an imbalanced reduction in T cell subtypes leading to a greater proportion of effector T cells
Tumor Treating Fields	• May increase tumoral PD-L1 expression	• May increase immune cell infiltration into tumors