Shikonin (SHK), a natural naphthoquinone pigment isolated from Lithospermum erythrorhizon, has been reported to suppress the growth of various cancer types in vitro, such as lung (Kim et al., 2017; Li et al., 2018; Fayez et al., 2020), breast (Du et al., 2020; Wang et al., 2021), skin (Li et al., 2015), gallbladder (Zhai et al., 2017), glioma (Ma et al., 2020), and prostate (Gara et al., 2015). Here, SHPK is linked to cancer.