According to Wu et al, miR‐19a/b was overexpressed in gastric cancer tissues and could promote metastasis by regulating tumor suppressor MXD1.46 However, according to another study, miR‐19‐3p showed to be a tumor suppressor in breast cancer by inhibiting cancer cell proliferation and changing saracatinib resistance status via targeting PI3K/Akt pathway.47 It indicates the duplicity of miR‐19b‐3p in cancers.48 Circulating miR‐19b‐3p has also been found to be reliable biomarker for various diseases. This evidence concerns the gene MXD1 and breast cancer.