ABSTRACT
PURPOSE: Sensitive detection of systemic tumor dissemination in lung cancer patients is important for selection of appropriate treatment modalities. Based on recent promising data that showed reverse transcriptase-polymerase chain reaction (RT-PCR) analyses for cytokeratin 19 (CK-19) expression in peripheral-blood or bone marrow samples to be a rapid and highly sensitive method for detection of hematogenous tumor dissemination in patients with breast and prostate cancer, we evaluated the specificity of this assay system in lung cancer patients and a large number of healthy controls. PATIENTS AND METHODS: We examined CK-19 mRNA expression by RT-PCR in 17 lung cancer cell lines and in peripheral-blood samples of 50 lung tumor patients and 65 healthy controls. RESULTS: Expression of CK-19 mRNA was observed in all lung cancer cell lines and in 50% of peripheral-blood samples from lung tumor patients. However, under the experimental conditions analyzed, at least 20% of the control samples were positive for CK-19 mRNA expression. CONCLUSION: Contrary to prior reports, RT-PCR may detect non-tissue-specific constitutive low-level (illegitimate) expression of CK-19 mRNA in peripheral-blood mononuclear (PBMN) cells in a significant number of healthy controls. This finding may not only hamper the use of this assay system in lung cancer patients, but also questions its proposed applicability in patients with other epithelial tumors such as breast and prostate cancer.
Subject(s)
Keratins/genetics , Lung Neoplasms/pathology , RNA, Messenger/analysis , Adult , Aged , Base Sequence , Female , Humans , Leukocytes, Mononuclear/chemistry , Lung Neoplasms/blood , Lung Neoplasms/genetics , Male , Middle Aged , Molecular Sequence Data , Neoplasm Metastasis , Polymerase Chain Reaction , RNA, Messenger/blood , Sensitivity and Specificity , Transcription, GeneticABSTRACT
Human chromosomal region 3p12-p23 is proposed to harbor at least three tumor suppressor genes involved in the development of lung cancer, renal cell carcinoma, and other neoplasias. In order to identify one of these genes we defined sequence tagged sites (STSs) specific for 3p13-p24.2 by analyzing a chromosome 3p14 microdissection library. STSs were used for isolating yeast artificial chromosome (YAC) clones from the Centre d'Etude du Polymorphisme Humain (CEPH) YAC libraries. Thirty-eight YACs were assembled into a contig approximately 2.5 Mb in size spanning the t(3;8) and t(3;6) translocation breakpoints associated with hereditary renal cell carcinoma and hematologic malignancies, respectively. Chromosomal localization and chimeric status of 126 YACs was analyzed by fluorescence in situ hybridization (FISH). The order of 17 YACs determined by double-color FISH was in agreement with the STS-based arrangement of the YAC-contig.
