Dual-mode microfluidic immunostaining device for diagnostic biomarkers detection and tumor microenvironment evaluation.

The limited availability of tissue samples from rare tumors poses a major barrier to advances in precise diagnosis, prognostic evaluation, and therapeutic research-challenges exemplified by primary central nervous system diffuse large B cell lymphoma (PCNS-DLBCL). Here, we developed a dual-mode microfluidic immunostaining (Dumi) device, which integrates diagnostic and research workflows into a single, automated platform, reducing tissue section consumption by more than 90%. Using just one to two slides, it enables both regional detection of biomarkers for diagnostic subtyping (≤16) and construction of multiplex tumor microenvironment (TME) maps. Joint analysis of multiregion diagnostic biomarkers in the TME map indicates that tumor cell subpopulations defined by specific diagnostic biomarkers can actively shape their in situ microenvironmental niche. Dumi offers an efficient, cost-effective, and multifunctional immunostaining method, overcoming the limitations of scarce tissue resources and providing a clinically accessible solution to the diagnostic and therapeutic challenges with rare tumors.