TERT and esophageal squamous cell carcinoma: Using Power and Sample Size Calculation (PS, version 3.0, 2009, http://biostat.mc.vanderbilt.edu/twiki/bin/view/Main/PowerSampleSize) and considering TERT-CLPTM1L rs401681 C>T mutant alleles in the control group, ORs, ESCC samples and control samples, the power of our analysis (α = 0.05) was 0.708 in 604 ESCC cases and 664 controls, with an OR of 0.74.