Identification of differentially expressed genes in esophageal squamous cell carcinoma (ESCC) by cDNA expression array: overexpression of Fra-1, Neogenin, Id-1, and CDC25B genes in ESCC.
OBJECTIVE
This study aims to identify differentially expressed genes in esophageal squamous cell carcinoma (ESCC) through the use of a membrane-based cDNA array.


METHODS
Two newly established human ESCC cell lines (HKESC-1 and HKESC-2) and one corresponding to a morphologically normal, esophageal epithelium tissue specimen, prospectively collected from the HKESC-2-related patient, were screened in parallel using a cDNA expression array containing gene-specific fragments for 588 human genes spotted onto nylon membranes.


RESULTS
The results of cDNA expression array showed that 53 genes were up-regulated 2-fold or higher and 8 genes were down-regulated 2-fold or higher in both ESCC cell lines at the mRNA level. Semiquantitative RT-PCR analysis of a subset of these differentially expressed genes gave results consistent with cDNA array findings. Four of the differentially expressed genes that belong to the categories of oncogenes/tumor suppressor genes (Fra-1 and Neogenin) and cell cycle-related genes (Id-1 and CDC25B) were studied more extensively for their protein expression by immunohistochemistry. The two ESCC cell lines and their corresponding primary tissues, 61 primary ESCC resected specimens and 16 matching, morphologically normal, esophageal epithelium tissues were analyzed. The immunostaining results showed that Fra-1, Neogenin, Id-1, and CDC25B were overexpressed in both ESCC cell lines and their corresponding primary tumors at the protein level, validating the microarray findings. The results of the clinical specimens showed that the Fra-1 gene was overexpressed in ESCC compared with normal esophageal epithelium in 53 of 61 cases (87%), Neogenin in 57 of 61 cases (93%), Id-1 in 57 of 61 cases (93%), and CDC25B in 48 of 61 cases (79%). Furthermore, the expression of Fra-1, Neogenin, and Id-1 in ESCC correlated with tumor differentiation.


CONCLUSIONS
Overall, this study demonstrates that multiple genes are differentially expressed in ESCC and provides the first evidence that oncogenes Fra-1 and Neogenin and cell cycle-related genes Id-1 and CDC25B are overexpressed in ESCC.
Hu
Y C
YC
Department of Pathology, Faculty of Medicine, The University of Hong Kong, Queen Mary Hospital, Pok Fu Lam Road, Hong Kong.
Lam
K Y
KY
Law
S
S
Wong
J
J
Srivastava
G
G
D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D018797:Cell Cycle Proteins / Q000032:analysis / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics; D004938:Esophageal Neoplasms / Q000235:genetics* / Q000473:pathology; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D051798:Inhibitor of Differentiation Protein 1; D008565:Membrane Proteins / Q000032:analysis / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000032:analysis / Q000235:genetics; D014407:Tumor Cells, Cultured; D020687:cdc25 Phosphatases / Q000032:analysis / Q000235:genetics; D000099169:Fos-Related Antigen 1
D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D051798:Inhibitor of Differentiation Protein 1; D008565:Membrane Proteins; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D012097:Repressor Proteins; D014157:Transcription Factors; D020687:cdc25 Phosphatases; D000099169:Fos-Related Antigen 1; C497453:ID1 protein, human; C091279:neogenin; C517008:CDC25B protein, human