Cytometry with DAPI-stained tumor imprints. A reliable tool for improved intraoperative analysis of lung neoplasms

To determine the feasibility and potential use of application of 4'-6-diamidino-2-phenylindole dihydrochloride-stained imprints taken from primary lung carcinomas for intraoperative frozen section service.

Tumor imprints taken from intraoperative sections were stained with the fluorochrome DAPI, and the integrated nuclear fluorescence (INF) was measured using an automated image analyzing system. The 40 cases studied comprised all major lung carcinoma types as well as intrapulmonary metastases. The measured features included percentage of tumor cells > 3C and > 5C, S-phase-related tumor cell fraction, 2 CV standard deviation and INF entropy.

Test series with imprints of tumor-free lymph nodes revealed a minimum staining time of five minutes at 40 degrees C that led to reproducible staining intensities and size of the nuclear area. No significant differences were apparent in comparison to concomitantly performed measurements of the integrated optical density of "classical" Feulgen-stained specimens for each case. The fluorometric results could be submitted to the surgeon with 15-18 minutes (20 maximum).

The data indicate that cytometric DNA measurements can be performed intraoperatively with reliable quality within time schedules acceptable for intraoperative surgical strategies.