From the knockdown or overexpression experiments of ADAMTS9-AS2 in an MCF7-derived tamoxifen-resistant cell line, it is shown that ADAMTS9-AS2 acts as a ceRNA by sponging miR-130a-5p to promote the expression of a miR-130a-5p target gene, phosphatase and tensin homolog (PTEN), which is a well-known tumor-suppressor and enhances tamoxifen sensitivity (Figure 2) [45]. This evidence concerns the gene ADAMTS9 and neoplasm.