Progressive increase of apoptosis in prostatic intraepithelial neoplasia and carcinoma: comparison between in situ end-labeling of fragmented DNA and detection by routine hematoxylin-eosin staining.

OBJECTIVE

Apoptosis has attracted significant attention in the study of tumors during recent years. The first goal of this study was to evaluate the number of apoptotic cells and bodies in benign glands, in high-grade prostatic intraepithelial neoplasia, and in malignant prostatic glands. The second objective was to compare the effectiveness of in situ end-labeling of fragmented DNA (ISEL) with the use of routine hematoxylin-eosin (H&E) stains in the assessment of apoptosis rates.

METHODS

The percentage of apoptosis was measured with ISEL and H&E stains in sections from 16 prostatectomies performed for previously untreated peripheral prostatic adenocarcinomas.

RESULTS

Both methods showed progressive increase of the rates of apoptosis from benign glands (0.34% to 0.38%), to high-grade prostatic intraepithelial neoplasia (1.44% to 1.39%), to carcinoma (2.69% to 2.75%). The increase in apoptosis rate in prostatic intraepithelial neoplasia and carcinomas is one more indication of the continuum in the pathogenetic process leading to invasive prostatic carcinoma. Student's t test revealed no statistically significant difference in the percentage of apoptosis rendered by ISEL and H&E staining.

CONCLUSIONS

From a practical point of view, evaluation of apoptosis with H&E stains can be readily performed using routine clinical material. The procedure is inexpensive, and it gives good tissue morphology. However, quantitative measurements may be time-consuming and observer-dependent. The apoptotic bodies are clearly identifiable with ISEL, making quantitation easy and even amenable to automated counting methods. Disadvantages of ISEL are significantly higher costs and poor tissue morphology. We conclude that accurate evaluation of apoptosis may be performed reliably with both routine H&E staining and the ISEL method. The decision to choose one method over the other depends on the economic resources available and the amount of material to be evaluated.