ENO2 and laryngotracheoesophageal cleft: A 2013 study from China found that the combination of CEA, CYFRA 21-1, and NSE to be the optimal combination for LC diagnosis, with a sensitivity of 75.76% and specificity of 88.57%; it is noteworthy that this study did not evaluate ProGRP, either alone or in combination (Wang et al., 2013).