Also, in the study of Mhawech et al., which was conducted in the United States and Switzerland, the positive expression of Ck-7 was observed in 27.5% of PAC samples with a Gleason score of 8 or higher, and in 75% of cases, the expression of Ck-7 and Ck-20 were simultaneously negative (17). The gene discussed is KRT20; the disease is gonorrhea.