CT83 and cancer: Kita-Kyushu lung cancer antigen 1 (KK-LC1), encoded by cancer/testis antigen 83 (CT83), is a single-pass membrane protein normally expressed in testis, and other cancer types including lung cancer (Fukuyama et al., 2006; Jin et al., 2018; Marcinkowski et al., 2019; Ichiki et al., 2020).