Phenotypic characterization of TTMV/RARA fusion transcript. (A) Detection of the TTMV/RARA chimeric fusion in cDNA of patient 2 diagnosis and relapse and of the index case for comparison. Patient 2 carried a longer insert sequence from TTMV ORF2, with respect to the index case (Pt1). (B) Overexpression of the top-scoring M3-AML–specific genes in the 2 cases carrying TTMV-RARA chimeric fusion (blue bars) similarly to the 11 APL cases from the SRA bioproject PRJNA721935 (red bars) and with respect to another 15 non-APL AML samples lacking cytogenetic and molecular aberrations (light green bars). The plot reports gene expression quantification as log₂ ratios of transcripts per kilobase million (TPM); P value vs non-APL AML: *P < .05; **P < .01; ***P < .001. (C) Expression of TTMV-RARA by quantitative PCR in the HEK-293 cell line either parental or transfected with cloned full-length TTMV-RARA fusion transcript: P < .0001. (D) Flow cytometry assessment of TTMV/RARA fusion protein expression evaluated by means of AcGFP positivity in HEK-293 cells transfected with cloned full-length TTMV-RARA in frame with the AcGFP fluorescent tag sequence. (E) Effect of different ATRA concentrations on cell growth of U937 cells transfected with cloned full-length TTMV-RARA compared with the parental cell line after 4 days of treatment (*P < .05; **P < .01; ***P < .001).