Digistain: a novel biomarker imaging platform for grading breast carcinoma using routinely processed paraffin sections

Objective: Digistain is a new technology platform that enables imaging and quantification of a newly conceived biomarker for grading breast carcinoma in routinely processed, unstained paraffin sections without the use of traditional stains or contrasting agents. By recording a unique optical signature to analyze the chemical make-up of a biopsy quantitatively, the technique is unaffected by the subjectivity of traditional grading. Within minutes of loading a slide it yields a highly reproducible and user independent numerical score reflecting the cellularity of the tumour and its nuclear: cytoplasmic ratio. We report here our findings using an objective technique to grade breast tumours using quantitative criteria. Method: H&E stained sections from excision biopsies of 105 cases of invasive breast carcinoma were reviewed and graded using the ElstonEllis grading system. Unstained sections from each case were loaded into the Digistain platform to yield a numerical score - the Digistain Index (DI). Results: The cases were grouped according to histological grading. Mean DIs was calculated for each grade (1,2 and 3) to be 0.56, 0.61, and 0.68 respectively with a maximum standard error of 0.02. The DI spread within each grade was less than that across the three grades, thus validating this index as a viable grading indicator within the context of this study. Conclusion: We believe the new Digistain approach provides for the first time a cost effective and quantitative measure of tumour grade. This can be developed to deliver an effective assessment of prognosis and recurrence risk beyond traditional qualitative measures based on H&E staining protocols.