title: Array-based comparative genomic hybridization of circulating esophageal tumor cells.
abstract: Esophageal squamous cell carcinoma (ESCC) shows a high frequency of lymphatic and/or systemic metastasis, even when the tumor invades only the submucosa. To investigate the genetic alterations in circulating esophageal tumor cells, we performed array-based comparative genomic hybridization (CGH) analysis of 8 DNA samples of xenografts, which were previously established from the thoracic duct lymph of 13 ESCC patients. A total of 5 loci (or genes), 10q21.3 (EGR2), 11q13.3 (CCND1/CyclinD1, FGF4, and EMS1), 11q14 (PAK1), and 22qtel (ARSA) were found to be candidate amplified loci in the xenograft. In contrast, a total of 24 loci including 9p21 (p16 and MTAP) were found to be homozygously deleted candidates in the xenograft. Both p16 homozygous deletion and CCND1 amplification were detected in 6 (75%) and 5 (62.5%) of the 8 xenografts. Furthermore, by quantitative Southern blot analysis, we found p16 homozygous deletion in 30.8% (8/26) of the primary tumors and in 50% (4/8) of the metastasized lymph nodes. The frequency of CCND1 amplification and p16 homozygous deletion is suggested to be associated with ESCC progression. Matrigel invasion assays of p16-deleted ESCC cells showed that restoring wild-type p16 activity into the cells significantly inhibits tumor-cell invasion, suggesting that p16 inactivation could be involved in ESCC invasion. This is the first report showing the genetic alteration of concealed tumor cells in the thoracic duct lymph. The present gene list should be helpful for identifying new amplified and deleted genes in primary ESCCs as well as in metastasized lymph nodes.
authors.affiliation: Division of Genetics, National Cancer Center Research Institute, Chome, Tokyo 104-0045, Japan.
authors.forename: Dal Ho
authors.initials: DH
authors.lastname: Kim
authors.forename: Manabu
authors.initials: M
authors.lastname: Muto
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Kuwahara
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Nakanishi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watanabe
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Aoyagi
authors.forename: Kenji
authors.initials: K
authors.lastname: Ogawa
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Yoshida
authors.forename: Hiroki
authors.initials: H
authors.lastname: Sasaki
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D015139:Blotting, Southern; D002294:Carcinoma, Squamous Cell / Q000097:blood* / Q000235:genetics* / Q000473:pathology; D019938:Cyclin D1 / Q000235:genetics; D004938:Esophageal Neoplasms / Q000097:blood* / Q000235:genetics* / Q000473:pathology; D005784:Gene Amplification; D017353:Gene Deletion; D018014:Gene Transfer Techniques; D019942:Genes, p16; D006801:Humans; D008207:Lymphatic Metastasis; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D013897:Thoracic Duct / Q000473:pathology; D014183:Transplantation, Heterologous
chemical_list: D019938:Cyclin D1