Proliferating cell nuclear antigen (PCNA) evaluation in the diagnostic quantitative pathology of cribriform adenocarcinoma of the prostate.

The aim of this study was to emphasise the importance of the measurement sites in tumours from the biological point of view. In particular, two distinct aspects regarding locations were investigated for Proliferating Cell Nuclear Antigen (PCNA) expression in the cribriform adenocarcinoma of the prostate as an example. The first aspect was the identification of the most suitable part of the tumour nodule to be analysed, that is, periphery or marginal zone vs central. The second aspect consisted of the precise location of the objects in relation to the histologic pattern and its components, such as the different cell layers in the cribriform pattern. The results obtained showed that the proportion of PCNA-immunostained nuclei in the marginal zone of the tumour decreased from the basal position, or adjacent to the stroma, towards the lumen: 14.40% (standard error, SE, 0.61%) in the basal position, 11.84% (SE 1.30%) in the intermediate and 9.26% (SE 0.66%) in the lumenal position. In the central zone of the tumour the trend of value changes was similar to that obtained in the marginal zone. However, the proportions were lower and the differences statistically significant. In conclusion, the degree of PCNA expression is related to both locations. Thus, adequate information on the biology of the lesions can only be obtained when the precise site of the objects to be evaluated is identified. Otherwise, misleading results about the lesions being measured can be derived.