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.

It is established that subtypes of human malignant mesotheliomas (MM) are associated with different survival times. Ninety cases of MM were examined using DNA cytometry and comparative genomic hybridization (CGH), with emphasis on the main histological subtypes; epithelioid, sarcomatoid and biphasic. A comparison by DNA cytometry revealed moderate differences, with the rare subgroup of mesodermomas having the highest and the sarcomatoid group the lowest rate of aneuploidy. Using CGH, 6.2 chromosomal imbalances per case on average could be detected. Losses (4.1/case) were more common than gains of chromosomal material (2.1/case). MM show no single, specific defect, but a typical pattern of genomic defects can be attributed to this tumour entity. Common losses are clustered at the chromosomal regions 9p21 (34%), 22q (32%), 4q31-32 (29%), 4p12-13 (25%), 14q12-24 (23%), 1p21 (21%), 13q13-14 (19%), 3p21, 6q22, 10p13-pter and 17p12-pter (16% each). Common gains are located on 8q22-23 (18%), 1q23/1q32 (16%), 7p14-15 and 15q22-25 (14% each). While differences in the frequencies of the defects between epithelioid and sarcomatoid MM are not as pronounced as are seen with the pleomorphic mesodermomas, several chromosomal locations (3p, 7q, 15q, 17p) show significant variations. The most pronounced distinguishing feature of sarcomatoid MM is a more than fourfold higher number of amplicons. These data indicate that MM has a distinctive tumour biology with a broad spectrum of heterogeneity, as reflected in morphology and also, more subtly, in the patterns of chromosomal imbalances of the subtypes.

Solitary fibrous tumours (SFTs) of the pleura, in contrast to malignant mesothelioma, occur independently of previous asbestos exposure. They are benign tumours, but may recur if the stalk to the adjacent pleural or lung tissue remains in situ during surgical removal. The molecular pathology of SFTs is largely unknown. We used comparative genomic hybridisation (CGH) to characterise 12 localised SFTs and 12 predominantly sarcomatoid mesotheliomas. Fifty-eight percent of the investigated SFTs did not show any chromosomal imbalances. The most frequent defects were losses on chromosome arms 13q (33%), 4q and 21q (17% each). Significant gains were seen at chromosome 8 and at 15q in two cases each. There was no correlation between tumour size and molecular pathology findings. In contrast, 75% of the mesotheliomas carried chromosomal defects. On average, the mesotheliomas showed over three times as many defects per tumour as the SFTs. Localisation of several frequent losses and gains were similar to those of the SFTs. Therefore, in individual cases, a clear distinction between SFTs and sarcomatoid mesotheliomas is not possible based on CGH analysis alone. Further molecular characterisation of this rare tumour entity will be necessary to elucidate possible genes involved in early tumorigenesis.

In patients suffering from a variety of severe diseases the detection of erythroblasts in peripheral blood is associated with poor prognosis. However, as yet the prognostic significance of erythroblasts in the blood of patients after cardiothoracic surgery has not been assessed. In a retrospective study we analyzed the database of 2074 patients, of whom 87 died in hospital during the postoperative period. All patients underwent cardiothoracic surgery using a heart-lung machine. Together with erythroblasts in blood, age, sex, body mass index, preoperative ejection fraction, smoking, diabetes mellitus, type of operation, emergency surgery, renal deficiency, pulmonary hypertension, and endocarditis were considered. The postoperative mortality of patients with erythroblasts in peripheral blood (n=57) was 45.6% (n=26), being significantly higher (p<0.001) than the mortality of patients without erythroblasts (3.0%). None of six patients with more than 2000 erythroblasts x 10(6)/l survived. The postoperative detection of erythroblasts is highly predictive of death, the odds ratio after adjustment for the other known prognostic factors being 7.2 (95% confidence interval 3.4-15.1). Erythroblasts were detected for the first time on average 11 +/- 2 days (median: 7 days; n=57) after surgery and 8 +/- 2 days (median: 6 days; n=26) before death. The detection of erythroblasts in blood after cardiothoracic surgery has a high prognostic significance in terms of in-hospital mortality, helping physicians to identify patients at high risk of death. This finding has to be confirmed by a prospective study with the use of a more sensitive and reliable technology and prospectively defined time intervals for counting blood cells.

Malignant mesotheliomas are tumors known for their extensive heterogeneity. Apart from the three classical patterns, predominantly epithelioid, sarcomatoid, and biphasic, some rare variants do exist. In some cases, one can find uncommon additional mesodermal tumor components. These tumors have previously been called "mesodermomas" and, like regular mesotheliomas, are usually associated with a previous asbestos exposure. We examined eight cases of mesodermomas by light microscopy, immunohistochemistry and comparative genomic hybridization (CGH). Besides biphasic and epithelioid areas, unusual epithelial, chondroid, osseous, or even angioblastic elements may be found to varying degrees. Immunohistochemical analysis shows similar staining results as with regular mesotheliomas. CGH reveals a high number of chromosomal imbalances (16.5 per case; range, 11-27). In 10 classical biphasic mesotheliomas that served as a control, defects of comparable number and severity could not be detected (8 per case; range, 2-16). The most frequent defects of mesodermomas (losses on 1p, 4pq, 9p, 13q, 14q, and gains on 1q and 15q), however, could also be found in mesotheliomas of the classical type. Thus, our results support the classification of the so-called mesodermomas as a separate tumor subgroup while maintaining the relationship to the classical mesotheliomas. Therefore, we propose to use the term mesodermoma for this subgroup.