In conclusion, our research identified and developed a novel stemness-index-related lncRNA signature for predicting the prognosis of BC patients based on six stemness-index-related lncRNAs (FAM83H-AS1, HID1-AS1, HOXB-AS1, RP11-1070N10.3, RP11-1100L3.8, and RP11-696F12.1). This evidence concerns the gene SACK1H and breast cancer.