Despite their scarcity, the overall tumor content of cDC1s, as assessed by cDC1-specific signatures in gene expression data and/or by flow cytometric analysis, positively correlates with cancer patient survival across multiple cancers and is predictive of the responsiveness to anti–PD-1 immunotherapy in melanoma patients 10, 26, 27, 28. The gene discussed is MPPE1; the disease is neoplasm.