TSIX and breast cancer: In addition to the uncertain mechanism of interaction between lncRNAs XIST, TSIX, and PD-L1, another limitation of this study is the unrevealed mechanistic contribution of both lncRNAs XIST and TSIX in BC progress as our main concern was exploring a correlation between lncRNAs XIST, TSIX, and PD-L1 expression in BC patients.