Proteomic and genomic studies conducted by our team pointed out different elements of the UPS as breast cancer prognostic markers: ubiquitin as a prognostic protein marker in node-negative (N-) patients, and UBE2C, PSMA5, PSMB3, PSMB7, and PSMD3 as prognostic nucleic acid markers in node-positive (N+) patients, respectively (Ricolleau et al, 2006; Campone et al, 2008; Jézéquel et al, 2008). The gene discussed is HMBS; the disease is breast cancer.