Abnormal expression of the GPX1, GPX4, SEP15, and selenoprotein P (SELENOP) genes has been detected in a variety of cancers, including gastric cancer (Lan et al., 2017), colon carcinoma (Yagublu et al., 2011), colorectal cancer (Hughes et al., 2018), clear cell renal cell carcinomas (Rudenko et al., 2015; Cheng et al., 2019), laryngeal squamous cell carcinoma (Zhang Q et al., 2018), breast cancer (Król et al., 2018), MCF-7 adenocarcinoma cells (Rusolo et al., 2017), lung cancer (Gresner et al., 2009), and HepG2 liver cancer cells (Guariniello et al., 2015; Zhao et al., 2015). The gene discussed is SELENOP; the disease is gastric cancer.