High K5/6 immunostaining (score 2 or 3) was present in 25% (2/8) of the benign serous cystadenoma (Figure 2C, Table 1A), 60% (6/10) high grade serous borderline tumors (Figure 2D, Table 1A) and 29.9% (35/117) of the serous ovarian cancer cases (Table 1A). Here, KRT5 is linked to ovarian serous adenocarcinoma.