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 over 90 %. Using just 1–2 slides, it enables both regional detection of biomarkers for subtyping diagnostic (≤ 16) and construction of multiplex tumor microenvironment (TME) maps. Joint analysis of multi-region 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 of rare tumors.