CDKL2 and breast cancer: In the Genecards database, papillary serous adenocarcinoma is included among the diseases associated with CDKL2. Moreover, recent studies have indicated that CDKL2 is associated with malignant tumors, such as prostate cancer (Rubicz et al., 2019), breast cancer (Li et al., 2014; Lindqvist et al., 2014), hepatocellular carcinoma (HCC) (Shen et al., 2012; Zhou et al., 2019), glioma (Yi et al., 2020), and gastric cancer (Fang et al., 2018).