The role of genetic markers--NAP1L1, MAGE-D2, and MTA1--in defining small-intestinal carcinoid neoplasia.
BACKGROUND
Standard clinical and immunohistochemical methods cannot reliably determine whether a small intestinal carcinoid (SIC) is indolent or aggressive. We hypothesized that carcinoid malignancy could be defined by using quantitative reverse transcriptase-polymerase chain reaction (QRT-PCR) and immunohistochemical approaches that evaluate potential marker genes.


METHODS
Candidate marker gene expression (nucleosome assembly protein 1-like 1 [NAP1L1], melanoma antigen D2 [MAGE-D2], and metastasis-associated protein 1 [MTA1]) identified by Affymetrix transcriptional profiling was examined by QRT-PCR in SIC, liver, and lymph node (LN) metastases, colorectal carcinomas, and healthy tissues. Immunohistochemical expression levels of MTA1 were analyzed quantitatively by a novel automated quantitative analysis in a tissue microarray of 102 gastrointestinal carcinoids and in a breast/prostate carcinoma array.


RESULTS
Affymetrix transcriptional profiling identified three potentially useful malignancy-marker genes (out of 1709 significantly altered genes). By QRT-PCR, NAP1L1 was significantly (P < .03) overexpressed in SIC compared with colorectal carcinomas and healthy tissue. Increased levels (P < .05) were identified in both liver and LN metastases. Levels in colorectal carcinomas were the same as in healthy mucosa. MAGE-D2 and MTA1 were increased (P < .05) in primary tumors and metastases and overexpressed in carcinomas. Automated quantitative analysis demonstrated the highest levels of MTA1 immunostaining in malignant primary SICs and in metastases to the liver and LN. These were significantly increased (P < .02) compared with nonmetastatic primary tumors. MTA1 was overexpressed in breast and prostate carcinomas (P < .05).


CONCLUSIONS
SICs overexpress the neoplasia-related genes NAP1L1 (mitotic regulation), MAGE-D2 (adhesion), and MTA1 (estrogen antagonism). The ability to determine the malignant potential of these tumors and their propensity to metastasize provides a biological rationale for the management of carcinoids and may have prognostic utility.
Kidd
Mark
M
Department of Surgery, Yale University School of Medicine, 333 Cedar Street, P.O. Box 208062, New Haven, Connecticut 06520-8062, USA.
Modlin
Irvin M
IM
Mane
Shrikant M
SM
Camp
Robert L
RL
Eick
Geeta
G
Latich
Igor
I
D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D000368:Aged; D000951:Antigens, Neoplasm / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002276:Carcinoid Tumor / Q000235:genetics* / Q000473:pathology; D018797:Cell Cycle Proteins / Q000378:metabolism*; D005260:Female; D005819:Genetic Markers; D006655:Histone Deacetylases / Q000378:metabolism*; D006801:Humans; D007414:Intestinal Neoplasms / Q000235:genetics* / Q000473:pathology; D007421:Intestine, Small; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins / Q000378:metabolism*; D056490:Nucleosome Assembly Protein 1; D012097:Repressor Proteins / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D046888:Tissue Array Analysis; D015534:Trans-Activators
D048868:Adaptor Proteins, Signal Transducing; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D005819:Genetic Markers; C451414:MAGED2 protein, human; C089320:MTA1 protein, human; C533557:NAP1L1 protein, human; D009687:Nuclear Proteins; D056490:Nucleosome Assembly Protein 1; D012097:Repressor Proteins; D015534:Trans-Activators; D006655:Histone Deacetylases