Govindarajan R, et al. - In this retrospective cohort analysis, researchers assessed the expression of programmed cell death-ligand 1 (PD-L1) in subjects with squamous cell carcinoma of the anal canal. Recurrence and survival were also investigated. They used Poisson regression to assess crude recurrence rates (CRRs), crude mortality rates (CMRs), and crude event rates (CERs) for PD-L1-dependent differences. All three types of crude rates were expressed as the number that occurred per hundred person-years (hPY) of follow-up. Findings revealed worse CRR and CER were related to PD-L1 positivity. PD-L1 positivity was also found to be related to marginally worse CMR.