First, we evaluated the expression of circHIPK3 (the second exon of HIPK3, position chr11:33,307,958–33,309,057 (hg19), Figure 1A) and the corresponding linear transcript in non-malignant (n = 4) and metastatic (n = 7) BC cell lines (Hedegaard et al., 2016; Okholm et al., 2017) using the CIRI2 pipeline (Gao et al., 2018). The gene discussed is HIPK3; the disease is breast cancer.