PSMB7 and osteosarcoma: Distinctly, in osteosarcoma cells, LACTB is highly expressed in its mutant form LACTBM5L+R469K, which binds directly to proteasome subunit beta-type 7 (PSMB7), promoting p53 degradation while inhibiting the nuclear export of the p53R156P variant, thus exhibiting oncogenic properties (Figure 3) [36].