Improved DNA content histograms from formalin-fixed, paraffin-embedded liver tissue by proteinase K digestion

Flow Cytometry: Principles and Clinical Applications in Hematology

The use of flow cytometry in the clinical laboratory has grown substantially in the past decade. This is attributable in part to the development of smaller, user-friendly, less-expensive instruments and a continuous increase in the number of clinical applications. Flow cytometry measures multiple characteristics of individual particles flowing in single file in a stream of fluid. Light scattering at different angles can distinguish differences in size and internal complexity, whereas light emitted from fluorescently labeled antibodies can identify a wide array of cell surface and cytoplasmic antigens. This approach makes flow cytometry a powerful tool for detailed analysis of complex populations in a short period of time. This report reviews the general principles in flow cytometry and selected applications of flow cytometry in the clinical hematology laboratory.

Diagnostic and prognostic value of DNA ploidy and cell nuclearity in ultrasound-guided liver biopsies

BACKGROUND

Focal nodule lesions in patients with cirrhotic livers may be visualized by using imaging techniques; however, the diagnostic and prognostic judgment of biopsies from borderline lesions may be difficult using conventional histologic criteria.

METHODS

The diagnostic and prognostic value of DNA ploidy analysis determined by image cytometry of Feulgen-stained isolated hepatocytes was investigated in ultrasound-guided biopsies from 50 nodular lesions found in patients with cirrhotic livers (39 hepatocellular carcinomas [HCCs] and 11 macroregenerative nodules) and from 10 patients with livers affected by viral chronic hepatitis. Of the 11 macroregenerative nodules, 7 presented a subsequent neoplastic behavior. Specimens from the morphologically normal livers of five patients who underwent liver surgery served as control tissues. Image cytometry was performed on Feulgen-stained cytologic preparations, obtained by enzymatic digestion of formalin fixed biopsies. The DNA ploidy of the main stem line and the distribution of mononucleated and binucleated hepatocytes (nuclearity) were compared using histologic diagnosis, Edmondson's grade, tumor size, and patient follow-up.

RESULTS

The main stem line was peridiploid in all benign specimens and in 31 clinically confirmed HCCs, peritetraploid in 11 HCCs, perioctaploid in 1 HCC, and aneuploid in 3 HCCs. The fraction of mononucleated polyploid hepatocytes was found to be the best diagnostic parameter in euploid HCCs and was significantly correlated with the Edmondson grade and the nodular size. Survival information was available for 43 patients, with a median observation period of 350 days. A DNA ploidy value of the main stem line greater than 3c was an important determinant of survival as a single parameter and in association with histologic grade and greatest dimension of tumor.

CONCLUSIONS

This study suggests that the ploidy distribution analysis of mononucleated and binucleated hepatocytes can provide valuable information for making correct diagnoses and for predicting survival outcome for patients with HCCs.