Many studies have shown that abnormal expression of Arp2/3 subunits is associated with the proliferation and invasion of various cancers, including pancreatic cancer (Rauhala et al., 2013), gastric cancer (Zhang et al., 2017a), colorectal cancer (Su et al., 2018), breast cancer (Chen et al., 2019; Cheng et al., 2019), bladder cancer (Chen et al., 2019; Cheng et al., 2019), gliomas (Liu et al., 2013), lung squamous cell carcinoma (lung SCC) (Moriya et al., 2012), and head and neck squamous cell carcinoma (HNSCC) (Kinoshita et al., 2012). The gene discussed is ACTR2; the disease is breast carcinoma.