[Fluorescence in situ hybridization. A new diagnostic dimension in cytology]

[Pleural mesothelioma. Cytology and molecular diagnostics]

The definitive diagnosis of malignant mesothelioma (MM) in effusion cytology is often avoided or reluctantly made by cytology alone. The most probable reason for this skepticism is the lack of expertise in cytology among many pathologists and clinicians. When an effusion specimen is composed of cells with unequivocal cytological features of malignancy that have the morphology and immunophenotype of mesothelial cells, the cytological diagnosis of MM is straightforward. However, in the daily routine difficult cases of atypical mesothelial cells are often encountered and additional methods are required to establish an accurate diagnosis. In contrast to reactive mesothelial cells cells of MMs often harbor chromosomal aberrations, most frequently a polysomy in combination with a 9p21 deletion. These chromosomal aberrations can easily be detected by multitarget fluorescence in situ hybridization (FISH); therefore, FISH allows a reliable distinction between reactive mesothelial cells and MM cells. In order to be able to discriminate between MM and adenocarcinoma, an immunocytochemical panel consisting of different mesothelial and epithelial markers is very helpful. In most inconclusive cases of atypical mesothelial cells the combination of morphology, immunocytochemistry and FISH allows a better distinction between reactive mesothelial cells and MM in effusion cytology.

Targeting bladder tumor cells in voided urine of Chinese patients with FITC-CSNRDARRC peptide ligand

Objective

To study the practicality of the FITC-CSNRDARRC peptide ligand (containing the Cys–Ser–Asn–Arg–Asp–Ala–Arg–Arg–Cys nonapeptide) in diagnosing and monitoring bladder tumors.

Materials and methods

Between March 2011 and September 2011, 80 consecutive patients with radiographic abnormalities, localizing hematuria, other symptoms, or signs were studied using the FITC-CSNRDARRC ligand, urinary cytology (UC), and fluorescence in situ hybridization (FISH). The sensitivity and specificity of these three technologies were determined and compared. Cystoscopy and tissue biopsy were taken as the “gold standards” for bladder tumor diagnosis in this study.

Results

Twenty-nine out of 80 patients were diagnosed with a bladder tumor via histopathological examination. The FITC-CSNRDARRC ligand was positive in 23 out of 29 bladder tumor patients and produced false negatives in six (20.69%) patients. The UC was positive in six out of 29 bladder tumor patients and produced false negatives in 23 (79.31%) patients. The FISH was positive in 21 out of 29 bladder tumor patients and produced false negatives in eight (27.59%) patients. The overall sensitivity as verified by the FITC-CSNRDARRC ligand was much higher than in UC (79.31% versus 20.69%, P < 0.001) and was slightly higher than in FISH (79.31% versus 72.41%, P = 0.625). The sensitivity of FISH was significantly higher than that of UC (72.41% versus 20.69%, P < 0.001). Sensitivities of the FITC-CSNRDARRC ligand and UC by grade were 58.33% versus 8.3% for low-grade (LG) tumors (P = 0.031) and 94.12% versus 29.41% for high-grade (HG) tumors (P = 0.003), respectively. The advantage was maintained in terms of the detection of invasive tumors between the FITC-CSNRDARRC ligand and UC (90.48% versus 23.81%, P = 0.001) as well as between FISH and UC (85.71% versus 23.81%, P = 0.003). The specificities for the FITC-CSNRDARRC ligand, UC, and FISH were 100%.

Conclusion

Results show that the FITC-CSNRDARRC ligand is a promising noninvasive tool for diagnosis and surveillance in patients suspected of having a new bladder tumor.

Re-evaluation of histological diagnoses of malignant mesothelioma by immunohistochemistry

Background

In order to provide reliable tissue material for malignant mesothelioma (MM) studies, we re-evaluated biopsies and autopsy material from 61 patients with a diagnosis of MM from the period of 1980-2002.

Methods

Basic positive (Calretinin, EMA, Podoplanin, Mesothelin) and negative (CEA, Ber-Ep4) immunohistochemical (IHC) marker reactions were determined. If needed, more markers were used. Histological diagnoses were made by three pathologists. Survival data were calculated.

Results

49 cases (80%) were considered being MM by a high degree of likelihood, five more cases possible MM. Of the remaining seven cases, three were diagnosed as adenocarcinoma, three as pleomorphic lung carcinoma, in one peritoneal case a clear entity diagnosis could not be given. One of the possible MM cases and two of the lung carcinoma cases had this already as primary diagnoses, but were registered as MM.

With a sensitivity of 100%, Calretinin and CEA were the most reliable single markers. The amount of MM cells with positive immunoreactivity (IR) for Podoplanin and Mesothelin showed most reliable inverse relation to the degree of atypia.

In the confirmed MM cases, there had been applied either no IHC or between one and 18 markers.

The cases not confirmed by us had either lacked IHC (n = 1), non-specific markers were used (n = 4), IR was different (n = 1), or specific markers had not shown positive IR in the right part of the tumour cells (n = 3).

46 of the 49 confirmed and three of the not confirmed cases had been diagnosed by us as most likely MM before IHC was carried out.

Conclusions

In order to use archival tissue material with an earlier MM diagnosis for studies, histopathological re-evaluation is important. In possible sarcomatous MM cases without any positive IR for positive MM markers, radiology and clinical picture are essential parts of diagnostics. IHC based on a panel of two positive and two negative MM markers has to be adapted to the differential diagnostic needs in each single case. New diagnostic tools and techniques are desirable for cases where IHC and other established methods cannot provide a clear entity diagnosis, and in order to improve MM treatment.