CD8A and anal squamous cell carcinoma: The preoperative test displayed a mean CD4+ T lymphocyte count of 291.3 cell/μL and a CD8+ T lymphocyte count of 667.3 cell/μL. Based on the postoperative pathology, 12 patients (21.1%) had a tumor in the right colon, 26 patients (45.6%) had a tumor in the left colon, and 19 (33.3%) patients in rectum (including nine patients with anal squamous cell carcinoma).