EGFR and central nervous system cancer: Although the results indicate that EGFR-null glioma cells are responsive to Nimotuzumab, the mechanism of action is unclear and we cannot exclude the possibility that EGFR-null cells are sensitive to the reagent used to prepare Nimotuzumab, in this case, it is a buffer solution containing polysorbate 80 of unrevealed concentration which has been associated with cytotoxic effect on the cells [43]; the slight reduction in cell viability observed may be attributed to this effect.