For example, Rahat Jahan et al. reported that the combined diagnosis of trefoil factors and CA199 could further increase the sensitivity and specificity of CA199 in the diagnosis of EPC [36]; Jiayu Zhang and Sukhwinder Kaur both found that MUC5AC combined with CA199 has extremely high diagnostic value for PC [11, 37]. This evidence concerns the gene MUC5AC and pachyonychia congenita.