The association between CD99 and LMP-1 expression in nasopharyngeal carcinoma.
OBJECTIVE
To characterize the roles of LMP-1 and CD99 in nasopharyngeal carcinogenesis, we undertook this pilot study of LMP-1 and CD99 expressions in nasopharyngeal cancer (NPC).


METHODS
40 NPC tissue samples were grouped according to the WHO classification. Immunohistochemical studies were performed using monoclonal antibodies against EBV latent membrane protein 1 (LMP-1) and CD99 protein. In addition, CD99 expression was evaluated in 10 samples of non-neoplastic nasopharyngeal epithelium.


RESULTS
LMP-1 was detected in 12 of the 40 (30.0%) cases and its expression was found to be confined to epithelial tumor cells. WHO type I NPC samples were completely negative for LMP-1, whereas WHO type III NPC samples showed highest expression. Interestingly, CD99 was expressed in all of the non-neoplastic nasopharyngeal epithelium samples along the cytoplasmic border. CD99 expression was noted in NPC tumor cells (5 of the 40 cases, 12.5%) and in surrounding lymphoid stroma (23 of the 40 cases, 57.5%), but was not expressed in WHO type I NPC. In the 12 LMP-1 positive cases, 9 cases (75.0%) were CD99 negative, and 3 cases (25.5%) were CD99 positive. There was a statistical significance between LMP-1 and CD99 expression in lymphoid stroma.


CONCLUSIONS
Our results suggest that the LMP-1 induced down-regulation of the CD99 pathway is important in nasopharyngeal carcinogenesis, and that the expression of CD99 in lymphoid stroma may regulate immune response to NPC.
Kim
H S
HS
Department of Pathology, Chonnam National University Medical School, Gwangju, Korea.
Kim
J S
JS
Kim
J S
JS
Park
J T
JT
Lee
M C
MC
Juhng
S W
SW
Cho
J H
JH
Park
C S
CS
D000071443:12E7 Antigen; D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD / Q000235:genetics*; D015815:Cell Adhesion Molecules / Q000235:genetics*; D003598:Cytoskeletal Proteins; D006801:Humans; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D060588:LIM Domain Proteins; D009303:Nasopharyngeal Neoplasms / Q000235:genetics*; D018307:Neoplasms, Squamous Cell / Q000235:genetics; D020545:Respiratory Mucosa / Q000473:pathology / Q000502:physiology
D000071443:12E7 Antigen; D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules; D003598:Cytoskeletal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D060588:LIM Domain Proteins; C484380:PDLIM7 protein, human