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Expression of Hard α-Keratins in Pilomatrixoma, Craniopharyngioma, and Calcifying Odontogenic Cyst

Kaoru Kusama DDS, PhD, Yoichi Katayama MD, PhD, Keiko Oba DDS, Toshiyuki Ishige DDS, Yumiko Kebusa DDS, PhD, Jiro Okazawa DDS, PhD, Takao Fukushima MD, PhD, Atsuo Yoshino MD, PhD
DOI: http://dx.doi.org/10.1309/WVTRR1DXYMC8PBMK 376-381 First published online: 1 March 2005


To examine the properties of shadow and ghost cells, 3 kinds of antibodies were raised against human hair proteins and their immunoreactivity was examined in tumors expressing those cells: pilomatrixoma, 14 cases; craniopharyngioma, 17 cases; and calcifying odontogenic cyst (COC), 14 cases. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis and Western blot analyses demonstrated that 2 polyclonal antibodies, PA-HP1 and PA-HP 2, reacted strongly with type I acidic and type II neutral/basic hard α-keratins. The other monoclonal antibody, MA-HP1, reacted with type II neutral/basic hard α-keratins. Immunohisto-chemical examination revealed that all 3 antibodies reacted only with the hair shaft in sections of normal skin and dermoid cyst. In all pilomatrixoma cases, 3 antibodies reacted with the cytoplasm of transitional and shadow cells but not with that of basophilic cells. Positive reactions were found only in shadow cells of all 13 adamantinomatous craniopharyngiomas. In all COCs, the antibodies reacted only with ghost cells, not with other epithelial components. Immunoreactivity for phosphothreonine, detected in hard α-keratins, also was found in transitional, shadow, and ghost cells. The appearance of shadow or ghost cells might represent differentiation into hair in these 3 kinds of tumors.

Key Words:
  • Hard α-keratin
  • Shadow cell
  • Ghost cell
  • Pilomatrixoma
  • Craniopharyngioma
  • Calcifying odontogenic cyst
  • Immunohistochemistry