Considering the above, we decided to analyze the relationship between GSH concentration and the activity of glutathione enzymes (GST, GPx, and GR) in combination with bortezomib in vitro (doses of 1 nM, 2 nM, and 4 nM) and its proapoptotic effect on multiple myeloma cells, taking into account the variants of the GSTT1 and GSTM1 genes. The gene discussed is GSTM1; the disease is plasma cell myeloma.