Analysis of Immunohistochemical Expression of K19 in Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma Using Color Deconvolution-Image Analysis Method

K19 is an intermediate filament protein that has been investigated in oral squamous cell carcinoma (OSCC), but that has not been correlated with the amount of keratin produced within well-differentiated OSCC grade. The aim of the present study was to objectively analyze K19 immunoexpression in OSCC and to validate the utility of K19 in differentiation among grades of oral epithelial dysplasia (OED). Formalin-fixed tissues of 36 primary OSCC (22 well, 10 moderately, 4 poorly differentiated), 43 OED (23 mild, 8 moderate, 12 severe), and 11 normal oral epithelium (NOE) were included. K19 was immunostained using HRP-DAB method. The percentage of K19-positive area was found using color deconvolution program in ImageJ ® image analysis system (public domain software, National Institutes of Health, Bethesda, MD, USA) and analyzed using independent samples t tests and ANOVA test. K19 scores in NOE, mild, moderate and severe OED were: 1.8, 3.4, 21, and 50.3%, respectively, with significant association with the grade ( t test P