(Aperio). Pathologists initially reviewed each slide at low magnification to determine low power microscopic morphology, then increased magnification to 20× and reviewed 10 representative high power fields on each slide. Diagnosis of ovarian serous cystadenocarcinoma was verified, and tumor purity was determined as the proportion of tumor nuclei present compared to the total nuclei present on the slide. The tumor purity of the extracted specimen was calculated as the average purity score of the top and bottom slides. Quality control included a random review of 10% of slides by a second pathologist to verify consistency of reads.
