CDKN1A and breast cancer: LncRNA promoter of CDKN1A antisense DNA damage activated RNA (PANDAR), which is located in chromosome 6p21.2, functions an oncogene in many kinds of tumors, such as pancreatic ductal adenocarcinoma (Jiang et al., 2017), breast cancer (Li et al., 2019), gastric cancer (Liu et al., 2018), acute myeloid leukemia (Yang et al., 2018), retinoblastoma (Sheng et al., 2018), ovarian cancer (Wang et al., 2018), and colorectal and cervical cancer (Huang et al., 2017; Rivandi et al., 2019).