Fig. 3

Representative images of CK7-stained slides containing serial 10-fold dilutions of SiHa or HeLa cells in HEK cells. The slides were stained with hematoxylin and for cytokeratin (CK) 7 using 3,3’-diaminobenzidine (DAB) chromogen (brown cell nuclei: SiHa and HeLa cells (CK7 positive cells); purple/blue cell nuclei: HEK cells (CK7 negative cells, counterstained with hematoxylin)). 20X magnification