However, bortezomib shows severe side effects, such as peripheral neuropathy, in up to 64% of newly diagnosed multiple myeloma patients,17,18 largely due to off-target inhibition, by bortezomib’s boronic acid warhead19, of HtrA2/Omi, a serine protease involved in neuronal survival. This evidence concerns the gene HTRA2 and plasma cell myeloma.