Plasma Membrane TRPV4 Relocalization as a Mechanosensitive Prognostic Biomarker in Ductal Carcinoma In Situ

PurposeReliable prediction of invasive progression remains an unmet need in ductal carcinoma in situ (DCIS). Conventional histologic grading provides limited prognostic value. Building on mechanistic evidence that cell crowding in confined ducts engages a TRPV4-dependent mechanotransduction program, we evaluated plasma-membrane TRPV4 (PM-TRPV4) relocalization as a mechanosensitive, patient-level prognostic biomarker for progression to invasive ductal carcinoma (IDC). Experimental DesignIn a retrospective single-institution case-control study, we analyzed 44 patients with pure DCIS (24 progressed to IDC, 20 remained IDC-free [≥]5 years). Three board-certified pathologists independently scored PM-TRPV4 on whole-slide immunohistochemistry using a prespecified five-level membrane-localization rubric (linearly weighted Fleiss {kappa}=0.823, 95% CI 0.777-0.863). The primary endpoint was IDC-free survival assessed by Kaplan-Meier and Cox models with prespecified adjustment for histologic grade and estrogen receptor (ER) status. ResultsPM-TRPV4 positivity was associated with shorter IDC-free survival (log-rank p=0.040). In multivariable Cox models, PM-TRPV4 remained independently prognostic (adjusted HR=3.77; 95% CI 1.01-14.12; p=0.049) after accounting for grade and ER, whereas histologic grade itself was not prognostic (p=0.57). Restricting to lower-grade DCIS strengthened the association (OR=10.50, two-sided p=0.016) vs overall (OR=5.92, two-sided p=0.057). In lower-grade DCIS, 77.8% (14/18) of PM-TRPV4-positive cases progressed vs 25.0% (2/8) of PM-TRPV4-negative. ConclusionsPM-TRPV4 provides independent, mechanism-informed prognostic information beyond histologic grade and ER. Given the small, single-institution case-control design, findings are hypothesis-generating and support multi-institutional validation with standardized staining/scoring, external calibration, and [≥]10 years of surveillance, particularly to refine risk in lower-grade DCIS, where clinical decisions are most uncertain. Translational Relevance StatementCurrent DCIS management relies on histologic grade, which has variable reproducibility and offers little guidance for about 60% of patients with lower-grade disease. We show that plasma-membrane relocalization of TRPV4 (PM-TRPV4), a functional readout of pro-invasive mechanotransduction in crowded ducts, adds independent prognostic information beyond grade and ER. In our cohort (N=44; 24 events), PM-TRPV4 positivity was associated with shorter IDC-free survival and remained significant in multivariable models (adjusted HR 3.77; p=0.049), whereas grade was not prognostic. Exploratory analyses suggested larger effects in lower-grade DCIS (OR [~]10.5), identifying a subset at high risk (77.8% vs 25.0% progression). PM-TRPV4 achieved near-perfect inter-rater reliability (weighted kappa = 0.823) using standard IHC on routine FFPE sections, supporting practical deployent. If externally validated with standardized protocols and at least 10 years of surveillance, PM-TRPV4 testing could enable personalized risk stratification and help select lower-grade DCIS patients for active surveillance versus those requiring escalation.