ObjectivesSince conventional cytogenetic analysis for bronchogenic carcinogenesis is limited by the difficulty to get enough number of high quality metaphase spreads, the development of new method to overcome above problems is strongly needed. Therefore, the introduction of non-radioactive in situ hybridization (ISH) with pericentromeric chromosome probes gave us the way to investigate the genetic events during carcinogenic process. We applied this method on lung cancer tissue to validate the possibility of this method for general usage and to analyze numerical chromosome aberration status and their clinical correlations.MethodsA set of satellite DNA probes specific for chromosome 3, 7, 9, 11, and 17 was hybridized directly to paraffin-embedded tissue section of 30 non-small cell lung cancers. Mean chromosome index of each chromosome and frequency of polysomy for each chromosome were calculated.ResultsMean chromosome indices for chromosome 3, 7, 9, 11, and 17 were 1.10, 1.13, 1.17, 1.12, and 1.17. respectively. Polysomy for a set of chromosomes was detected in all 30 cases except 4 cases which showed hypoploidy only for chromosome 3 or 7 in 2 cases and diploidy only for chromosome 3 or 11 in 2 cases. Among the set of chromosomes, mean chromosome index and polysomy frequency for chromosome 9 & 17 were significantly higher than that for others. Mean chromosome index or polysomy pattern for each chromosome was not much different among cell types or clinical stages.ConclusionsOur results show that chromosome ISH can be used to screen for numerical chromosome aberrations on paraffin tissue sections and further studies for ISH analysis with different probes on same tumor area or double-target ISH in large scale are needed to confirm above results and to elucidate the specific meanings.

To better understand the relationship between specific chromosome changes found in human lung tumors and their phenotypic consequences a the tissue level, an in situ hybridization (ISH) procedure of chromosome 17 and immunohistochemistry of proliferating cell nuclear antigen (PCNA) were done. The deparaffinized sections were stained with pericentromeric probes for chromosome 17 and an immunohistochemical study of a monoclonal antibody against PCNA were performed. The numbers of chromosome signals were than compared with the positivity of PCNA expression. The mean numbers of chromosome were 1.62 in normal lymphocytes and 2.48 in lung cancer cells. Tumors showed a high mean positivity of PCNA of 43.4%. Mean PCNA expression was higher in squamous carcinomas than in adenocarcinomas (p < 0.05). A linear correlation between numbers of ISH signals and PCNA expression was not demonstrated, but there was a tendency of increasing PCNA positivity according to increasing numbers of ISH signals in adenocarcinomas of the lung and the tumor tissues which were over 50% positive PCNA expression. There was no linear correlation between numbers of ISH signals, PCNA positivity and tumor stages, and keratinization of squamous cell lung cancer. These results suggest that ISH will prove to bo an important tool for determining the underlying genetic basis for tissue phenotypic heterogeneity by allowing genetic determinations to be made on paraffin-embedded tissue sections where histologic architecture is preserved, and immunohistochemical nuclear staining with anti-PCNA on routinely processed tissue is a simple technique for the assessment of proliferation in non-small cell lung carcinoma.