Up-regulation of neutrophil gelatinase-associated lipocalin in cholesteatoma.
CONCLUSIONS
Neutrophil gelatinase-associated lipocalin (NGAL) and Ki-67 expression were up-regulated in cholesteatoma and the expression pattern of NGAL in the epithelial layer was inversely related to the expression of Ki-67. Therefore, NGAL may be related to dysregulated differentiation in the keratinocytes during the development of a cholesteatoma.


OBJECTIVE
We investigated the differential expression and localization of NGAL in middle ear cholesteatoma and compared the results to normal external auditory canal (EAC) skin. We also compared the expression and localization of NGAL with the expression and localization of Ki-67 in middle ear cholesteatoma.


METHODS
Tissue samples from middle ear cholesteatomas and normal EAC skin were obtained from 20 patients undergoing middle ear surgery. NGAL mRNA expression was determined by the reverse transcriptase-polymerase chain reaction (RT-PCR). The expression of NGAL protein was analyzed by Western blot. NGAL and Ki-67 were localized by immunohistochemical staining.


RESULTS
A significantly greater expression of the NGAL mRNA was observed in cholesteatoma epithelium than in normal EAC skin (p < 0.05). NGAL was detected in the granular layer of cholesteatoma. However, NGAL was scarcely expressed in normal EAC skin. Ki-67 was detected predominantly in the basal and parabasal layers of cholesteatoma epithelium.
Woo
Hyun-Jae
HJ
Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, Yeungnam University, 317-1 Daemyung 5-Dong, Nam-Gu, Daegu, Republic of Korea.
Park
Jun-Chul
JC
Bae
Chang Hoon
CH
Song
Si-Youn
SY
Lee
Heung-Man
HM
Kim
Yong-Dae
YD
D000209:Acute-Phase Proteins / Q000302:isolation & purification / Q000378:metabolism*; D018424:Cholesteatoma, Middle Ear / Q000378:metabolism* / Q000473:pathology; D004424:Ear Canal / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D004848:Epithelium / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism; D000071068:Lipocalin-2; D054834:Lipocalins / Q000302:isolation & purification / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011518:Proto-Oncogene Proteins / Q000302:isolation & purification / Q000378:metabolism*; D015854:Up-Regulation
D000209:Acute-Phase Proteins; D019394:Ki-67 Antigen; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D011518:Proto-Oncogene Proteins