We observed that tumor-induced decrease in the expression of Notch receptors, Notch1, Notch2, Notch3 and Notch4, as well as ligands Dll1, Dll4 and Jagged1 in splenocytes of 4T1HA and RencaHA tumor-bearing mice could be reversed by treatment with bortezomib (Figure 4). The gene discussed is NOTCH1; the disease is neoplasm.