[Isolation and identification of DNA fragments frequently deleted from tumor cell lines of human esophageal cancer].
OBJECTIVE
To clone tumor suppressor genes associated with human esophageal cancer (EC).


METHODS
DNA fragments deleted from cell lines of esophageal cancer EC8712 and EC8733 were isolated by using modified genomic substractive hybridization. Twenty EC tissues paired with adjacent normal mucosa were analysed by Southern blot and PCR with these fragments as probes.


RESULTS
Seven DNA fragments deleted from EC cell lines obtained were named as 12H1, 12H2, 33H3, 33H4, 12B1, 33B2 and 33B3. Sequencing revealed their size of 512bp, 428bp, 509bp, 355bp, 680bp (partially sequencing), 519bp and 425bp, respectively. 12H1 and 33H3 showed high homology (98%) to a new repeated sequence in human genome. 33H4 displayed 87% nucleotide identity with human alphoid-like repetitive sequence located on chromosome 17. 12B1 was homologous (90%) to LINE 1 transoposon containing two open reading frames. 12H2, 33B2 and 33B3 were novel sequences. These DNA fragments were deleted in 20%-60% of EC tissues and in 10%-20% of adjacent mucosa.


CONCLUSIONS
Loss of 33H4 may be accompanied by deletion of an adjacent gene. 12B1 as transposon may suppress the tumorigenesis by activating suppressor genes or/and by inactivating oncogenes. 12H1/33H3, 12H2, 33B2 and 33B3 may be candidates of tumor suppressor genes associated with the development and the progression of esophageal cancer.
Department of Cell Biology, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing.
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Hou
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Wang
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Xu
D003001:Cloning, Molecular; D004273:DNA, Neoplasm / Q000235:genetics*; D004938:Esophageal Neoplasms / Q000235:genetics* / Q000473:pathology; D005260:Female; D017353:Gene Deletion; D016147:Genes, Tumor Suppressor; D006801:Humans; D007231:Infant, Newborn; D017422:Sequence Analysis, DNA; D014407:Tumor Cells, Cultured
D004273:DNA, Neoplasm