L1 is a potential marker for poorly-differentiated pancreatic neuroendocrine carcinoma.
OBJECTIVE
To determine the expression of L1 in pancreatic neuroendocrine tumor and to correlate it with WHO classification of this tumor.


METHODS
We retrospectively analyzed L1 expression in 63 cases of pancreatic neuroendocrine tumor by immunohistochemistry on paraffin sections of primary tumors or metastases. Staining was performed by peroxidase technique with monoclonal antibody UJ127.11 against human L1. All tumors were classified according to WHO classification as well-differentiated neuroendocrine tumors and carcinomas or poorly-differentiated neuroendocrine carcinomas.


RESULTS
L1 was detected in 5 (7.9%) of 63 pancreatic neuroendocrine tumors. Four (44.4%) of 9 poorly-differentiated carcinomas expressed L1. In contrast, only 1 (1.9%) of 54 well-differentiated tumors or carcinomas was positive for L1. No expression was found in Langerhans islet cells of normal pancreatic tissue. Cross table analysis showed a significant association between L1 expression and classification of neuroendocrine tumors of the pancreas (P<0.01).


CONCLUSIONS
L1 is specifically expressed in poorly-differentiated pancreatic neuroendocrine carcinomas that are known to have the worst prognosis. L1 might be a marker for risk prediction of patients diagnosed with pancreatic neuroendocrine carcinomas.
Kaifi
Jussuf T
JT
Department of General, Visceral and Thoracic Surgery, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany. jkaifi@uke.uni-hamburg.de
Zinnkann
Ulrich
U
Yekebas
Emre F
EF
Schurr
Paulus G
PG
Reichelt
Uta
U
Wachowiak
Robin
R
Fiegel
Henning C
HC
Petri
Susann
S
Schachner
Melitta
M
Izbicki
Jakob R
JR
D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D039842:Neural Cell Adhesion Molecule L1 / Q000032:analysis*; D018358:Neuroendocrine Tumors / Q000737:chemistry* / Q000145:classification / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000737:chemistry* / Q000145:classification / Q000473:pathology
D014408:Biomarkers, Tumor; D039842:Neural Cell Adhesion Molecule L1