In the 13 post-ART anal cancer studies, seven evaluated toxicity, and clinical outcomes using CD4 counts or viral load stratification and found no differences in toxicity (20, 27, 28), colostomy rates (20, 22), local recurrences (20), distant metastases (20), or overall survival (16, 20, 22, 26, 28, 29). The gene discussed is CD4; the disease is anal carcinoma.