In 2017 Tolkach and collaborators reported that all Y RNA are downregulated in BC (mean expression levels being 2- to 4-fold lower than in normal tissue) [69], with RNY1, RNY3, and RNY4 expression being highly correlated to each other, whereas RNY5 expression levels are less distinctly correlated with the other three. Here, RNY4 is linked to breast cancer.