Grand Erg Oriental follow the wind's direction. There are other types of dunes, as well as "complex" dunes. Saharan winds are also known to clear an area of sand altogether, leaving bare rock (hamada) or gravel (reg). The "Grand Erg Oriental" is accessible overland by an Algerian road, which goes south from Constantine. It passes through the Aurès mountains, then salt lakes by the city of Biskra. Next the road skirts the western edge of the erg. After about 500 km. in all, it reaches the ancient oasis of Ourgla [Wargla]. Since late antiquity Wargla was a stop for the Saharan trade, being
ERG (gene) TLS/FUS in Ewing's sarcoma and acute myeloid leukemias respectively and function as transcriptional activators. ERG and its fusion proteins EWS-ERG and TLS/FUS-ERG inhibit apoptosis. "ERG" can fuse with TMPRSS2 protein to form an oncogenic fusion gene that is commonly found in human prostate cancer, especially in hormone-refractory prostate cancer. This suggests that "ERG" overexpression may contribute to development of androgen-independence in prostate cancer through disruption of androgen receptor signaling. The fusion gene is critical to the progression of cancer because it inhibits the androgen receptor expression and it binds and inhibits androgen receptors already present in the cell. Essentially TMPRSS2-ERG