TARBP2 facilitates renal cell carcinoma immune escape by suppressing 53BP1 phase separation to upregulate B7-H3

Renal cell carcinoma (RCC) harbors an immunosuppressive tumor microenvironment that facilitates immune evasion and resistance to immune checkpoint blockade (ICB). However, the factors driving immune escape in RCC remain incompletely understood. In this study, transactivation response RNA-binding protein 2 (TARBP2) was identified as a critical regulator of the immune checkpoint molecule B7-H3. Elevated TARBP2 expression was associated with poor prognosis and ICB resistance in patients with RCC. Functionally, TARBP2 in RCC cells suppressed the intratumoral accumulation and cytotoxicity of T cells, particularly NK cells, thereby promoting immune escape. Mechanistically, nuclear TARBP2 interacted with p53-binding protein 1 (53BP1), inhibiting 53BP1 phase separation and subsequent p53 activation, thereby augmenting B7-H3 transcription. Furthermore, TARBP2 inhibition significantly enhanced ICB efficacy when combined with adoptive NK cell therapy. Collectively, these findings establish TARBP2 as a key mediator of immune evasion in RCC and a promising therapeutic target for overcoming ICB resistance.