Keratins and
secretory component (SC) were immunohistochemically examined in fresh tissue samples from 45 odontogenic and 35 non-
odontogenic cysts. Lining epithelia of almost all cases contained
keratins which reacted with polyclonal
antibodies (Dako, Bio-Science), and no difference could be found between the two groups of lesions. By staining with two
monoclonal antibodies against
keratins, i.e., RGE53 (Bio-Science) and RKSE60 (Bio-Science), it was revealed that the epithelia of non-
odontogenic cysts, which were columnar epithelium in most cases, had fully and positively reacted with RGE53, while none of the cases was positive for RKSE60. In contrast, the squamous linings of
odontogenic cysts except for two cases did not react with RGE53, and few cases possessed RKSE60-reactive
keratin. SC was also contradictory. All non-
odontogenic cysts exhibited SC. Regarding each pair of non-odontogenic and
odontogenic cysts covered with RGE53 and SC-positive, and RKSE60-negative squamous epithelium, it seemed reasonable from the staining results to conclude that the squamous linings were metaplastic from the columnar epithelium. Based on the results, concomitant examinations of SC with
keratins will be helpful in deciding the epithelial derivation of
jaw cysts.