However, due to highly specific mutated forms of RCC1 in a small number of cancer types, RCC1 could be used as a marker for diagnosis of these specific cancers, examples being the two highly specific fusion genes formed by RCC1 in testicular germ cell tumor (Hoff et al., 2016) and the RCC1 truncated mutation specifically observed in some Tunisian breast cancers (Hsu et al., 2016). The gene discussed is RCC1; the disease is breast cancer.