BCYRN1 and triple-negative breast carcinoma: However, POLR3G knockout in MDA-MB-231 triple negative breast cancer (TNBC) cells does not lead to significant changes in the steady-state levels of BC200, the small ncRNA encoded by BCYRN1, suggesting RPC7α enhancement may be context-dependent or may depend on additional factors (Lautré et al., 2022).