QuPath Analysis for CD30+ Cutaneous T-Cell Lymphoma

Background: Mycosis fungoides is the most common subtype of cutaneous T-cell lymphoma, in which the expression of cluster of differentiation 30 (CD30) + subtype can now be treated with the CD30 antibody conjugate brentuximab vedotin. Diagnostic methods are based on immunohistochemical (IHC) staining followed by manual assessment by pathologists, which is always a subjective calculation. QuPath, an open-source software for digital pathology image analysis, satisfies the requirements of objective approaches. Methods: Ten samples from mycosis fungoides patients with CD30 expression at different stages were stained for CD3 and CD30 by IHC staining, scanned, and quantitative analysis was performed using QuPath (version 2.1). Each slide was independently assessed by 3 board-certified dermatopathologists. Results: Individual estimates for CD30 + /CD3 + cells varied among the individual histopathologists (mean coefficient of variation, 0.46; range, 0–0.78). QuPath analysis showed excellent separation between the positively stained cells for CD3 and CD30 IHC and other cells and tissue structures, although the results correlated strongly with the respective mean estimates of the 3 histopathologists (Pearson-R 0.93). Conclusions: The results show a high interobserver variability evaluation of IHC markers, although quantitative image analysis offer a significant advantage for comparison. This is not only relevant for clinical routine but also especially critical in therapeutic studies addressing targeted molecules.