COL1A1 and prostate cancer: Another study identified miR-92a-1-5p as an abundant miRNA in exosomes from prostate cancer cells that directly target collagenase 1-A1 (Col1A1), promoting osteoclast differentiation and inhibiting osteoblastogenesis [69], which is quite a surprising finding knowing that prostate cancer metastases in bone have usually an osteoblastic phenotype.