PIR and breast cancer: We further investigated the effect of piR-36,712 in other subtypes of breast cancer cells, and found that overexpression of piR-36,712 significantly suppressed proliferation, migration and invasion of HCC1428 cells (luminal B subtype with wild type P53), whereas knockdown of piR-36,712 significantly promoted cell proliferation, migration and invasion (Additional file 2: Figure S6A-S6B and S6F-S6G).