RPS4Y1 and hepatocellular carcinoma: The same analyses performed on RNA samples from chorionic villi of a male and a female fetuses and from human hepatoma (HepG2) and human embryonic kidney (HEK293) cultured cells, used as unlimited source of biological material and derived respectively from a male and a female [27], confirmed the sex specific expression of the RPS4Y1 gene (Figure 1A).