title: Identification of two distinct tumor-suppressor loci on the long arm of chromosome 10 in small cell lung cancer.
abstract: Recent cytogenetic studies indicated that loss of the long arm of chromosome 10 is a frequent event in small cell lung cancer (SCLC) and that a common region of the deletion is at 10q24-qter, which suggests the presence of a tumor-suppressor gene there. To map precise tumor-suppressor loci on the chromosome arm for further positional cloning efforts, we tested 46 primary SCLCs using microsatellite analysis. By analysing 11 highly polymorphic microsatellite markers located in 10q23-q26, we found that at least 78% (36/46) of the tumors exhibited loss of heterozygosity (LOH) at 10q with at least two distinct minimally deleted regions. LOH at one region (10q24) was found in at least 74% (32/43) of informative cases with a minimally deleted region between D10S198 and D1OS192 (about 2 cM); LOH at another region (10q24-q25) was observed in at least 66% (29/44) of informative tumors with a minimally deleted region between D10S221 and D10S587 (about 11 cM). LOH at both regions or across both regions was observed in at least 52% (24/46) of the tumors tested. However, no mutations or homozygous deletions were found in the coding region of MXI1, a candidate tumor suppressor gene at 10q24-q25, in a panel of SCLC cell lines. Our data demonstrate that at least two tumor-suppressor loci exist on 10q and that they may play an important role in SCLC tumorigenesis.
authors.affiliation: Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston 77030, USA.
authors.forename: S K
authors.initials: SK
authors.lastname: Kim
authors.forename: J Y
authors.initials: JY
authors.lastname: Ro
authors.forename: B L
authors.initials: BL
authors.lastname: Kemp
authors.forename: J S
authors.initials: JS
authors.lastname: Lee
authors.forename: T J
authors.initials: TJ
authors.lastname: Kwon
authors.forename: W K
authors.initials: WK
authors.lastname: Hong
authors.forename: L
authors.initials: L
authors.lastname: Mao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D051792:Basic Helix-Loop-Helix Proteins; D018288:Carcinoma, Small Cell / Q000235:genetics*; D002879:Chromosomes, Human, Pair 10; D004268:DNA-Binding Proteins / Q000235:genetics; D005260:Female; D016147:Genes, Tumor Suppressor; D006801:Humans; D019656:Loss of Heterozygosity; D008175:Lung Neoplasms / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D014157:Transcription Factors / Q000235:genetics; D025521:Tumor Suppressor Proteins
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C079440:MXI1 protein, human