CASC9 accelerated ovarian cancer cell proliferation, invasion, and migration via acting as a competing endogenous RNA (ceRNA) for miR‐758‐3p to modulate LIN7A expression.21 CASC9 enhanced breast cancer cell proliferation and metastasis through positively regulating CHK1 via sponging the miR‐195/497 cluster 32 or through miR‐215/TWIST2 signaling.18 Elevated CASC9 promoted oral squamous cell carcinoma progression by inhibiting autophagy‐mediated apoptosis.20 However, the influence of CASC9 in PTC remains enigmatic. Here, CASC9 is linked to breast cancer.