Hydrolysis profiles of formalin fixed paraffin-embedded tumors based on IOD (integrated optical density) and nuclear texture feature measurements

The aim of the study was to determine optimal hydrolysis time for the Feulg en DNA staining of archival formalin fixed paraffin-embedded surgical sampl es, prepared as single cell suspensions for image cytometric measurements. The nuclear texture features along with the IOD (integrated optical density ) of the tumor nuclei were analysed by an automated high resolution image c ytometer as a function of duration of hydrolysis treatment (in 5 N HCl at r oom temperature). Tissue blocks of breast carcinoma, ovarian serous carcino ma, ovarian serous tumor of borderline malignancy and leiomyosarcoma were i ncluded in the study. IOD hydrolysis profiles showed plateau between 30 and 60 min in the breast carcinoma and leiomyosarcoma, and between 40 and 60 min in the ovarian sero us carcinoma and ovarian serous tumor of borderline malignancy. Most of the nuclear texture features remained stable after 20 min of hydrolysis treatm ent. Our results indicate that the optimal hydrolysis time for IOD and for nucle ar texture feature measurements, was between 40 and 60 min in the cell prep arations from tissue blocks of three epithelial and one soft tissue tumor.