In this study, we present microRNA transcriptome-wide analyses of compression-induced alterations in microRNA expression level in breast cancer cell lines [MCF-7(luminal A: ER+, PR+, HER2), BT-474(luminal B: ER+, PR+, Her2+), SK-BR-3(Her2: ER-, PR-, Her2+), MDA-MB-231(triple negative or Claudin-low: ER-, PR-, Her2-)] [21, 22] and cancer-associated fibroblasts (CAFs), a representative component of the tumor microenvironment, compressed at different relative compression units (RCUs). This evidence concerns the gene PGR and cancer.