THE INFLUENCE OF TISSUE PROCESSING ON QUANTITATIVE HISTOPATHOLOGY IN BREAST-CANCER

Objective grading of breast cancer by morphometry has been suggested for improving the precision of the prognostic prediction. However, the tissue components evaluated might be influenced by variations in the processing, reducing the clinical value. In the present study, the impact of the period of fixation, bf the acidity of the fixative and of the embedding medium was investigated by allocating tissue samples from 27 surgical breast cancer specimens systematically randomly to different modes of processing. The volume-weighted mean volume of cancer cell nuclei, ($) over bar v(v)(nuc), was estimated using the method of point-sampled intercepts on vertical sections. In addition, estimates of the mean nuclear profile area, ($) over bar a(H)(nuc), the nuclear volume fraction, V-v (nuc), the nuclear profile density, ND, and the mitotic profile frequency, MF, were obtained. The quantitative histopathological estimates were stable with respect to the investigated variables of the tissue processing. No significant differences were found when comparing the estimates obtained in samples from five tumours fixed in formalin at pH 5.0, 6.0, 7.0, 7.4 and 8.0, respectively. Similarly, no significant correlations between the estimates and the period of formalin fixation (24h, 3 days and 3 months) were found in samples from live other tumours. However, the ($) over bar v(v)(nuc) was 13% larger (2p = 0.004) and the mean ND 17% smaller (2p = 0.04) in hydroxyethyl-methacrylate-embedded samples from 17 tumours as compared to paraffin-embedded samples. Thus, the shrinkage observed in paraffin seems to affect nuclei less than tissue.