SPIN1 and breast cancer: MiRNAs act as key regulators in cancer initiation and progression, including cell proliferation, apoptosis, differentiation, invasion, metastasis and drug resistance.3, 4, 7, 10, 20 MiRNAs play roles as either tumour suppressors or oncogenes by negatively regulating their target genes.7 For example, miR‐489 inhibits breast cancer proliferation, metastasis and chemoresistance by suppressing SPIN1‐mediated PI3K‐Akt pathway.3, 21 Ma et al shows that Twist‐induced expression of miR‐10b initiated tumour invasion and metastasis in breast cancer.22