Single‐cell RNA sequencing of mycosis fungoides reveals a cluster of actively proliferating lymphocytes

Abstract

A 70‐year‐old man’s chronic erythematous skin lesion in the extremity had developed into a tumour one year before his first visit at our hospital. A biopsy showed atypical lymphocyte‐like cells, and immunostaining identified atypical cells as CD3+, CD4+, CD5+ and FOXP3+. Single‐cell RNA sequencing (scRNA‐seq) analysis using BD Rhapsody revealed the higher expression of CD3, CD4, CD5 and FOXP3 genes in a group of cells that highly expressed genes, such as PCNA, in the S/M phase, which is in agreement with immunofluorescence staining results. The use of scRNA‐seq analysis data is expected to promote personalised medicine for cutaneous lymphoma.