PML (15q22) and RARa(17q21) (t(15;17)(q21;q22))

A PML‑RARA test detects the PML‑RARA fusion gene caused by the t(15;17) chromosomal translocation. It confirms diagnosis of acute promyelocytic leukemia (APL), guides targeted therapy decisions, and monitors treatment response and minimal residual disease. The fusion is identified using molecular methods such as RT‑PCR or FISH, enabling rapid, sensitive detection for timely APL management.

T(15;17) in acute promyelocytic leukemia (APML) is a specific chromosomal translocation that creates a PML‑RARA fusion gene. The fusion protein disrupts retinoic acid receptor function, blocking myeloid differentiation and causing accumulation of promyelocytes with high risk of coagulopathy/DIC. It is diagnostic for APML and predicts sensitivity to targeted therapy with all‑trans retinoic acid and arsenic trioxide.

PML and RARA refer to genes that form the PML‑RARA fusion through a t(15;17) chromosomal translocation in acute promyelocytic leukemia (APL). PML encodes a nuclear protein involved in growth control; RARA encodes the retinoic acid receptor alpha that regulates cell differentiation. The fusion protein blocks myeloid maturation, causing leukemia, but is targetable with all‑trans retinoic acid and arsenic trioxide, which restore differentiation and remission.

The PML gene, located on chromosome 15q24.1, encodes the promyelocytic leukemia protein that organizes nuclear PML bodies and regulates apoptosis, senescence, DNA repair and antiviral responses. A balanced translocation t(15;17) fusing PML with RARA creates the PML‑RARA oncoprotein, which drives acute promyelocytic leukemia and disrupts normal cell differentiation and treatment response.

An APML test detects acute promyelocytic leukaemia (APML) by identifying the characteristic PML‑RARA gene fusion and abnormal promyelocytes. Diagnosis involves blood counts, bone marrow biopsy, and genetic assays such as karyotyping, FISH, or RT‑PCR to confirm PML‑RARA, guide urgent treatment (e.g., ATRA) and monitor minimal residual disease. Rapid testing is critical because APML can cause life‑threatening bleeding.

PML‑RARA is an oncogenic fusion protein from the t(15;17) translocation that blocks myeloid differentiation in acute promyelocytic leukemia. It functions as an abnormal retinoic acid receptor, recruiting corepressors and histone deacetylases to silence genes needed for maturation, and disrupts PML nuclear bodies, impairing apoptosis and DNA repair—driving accumulation of immature promyelocytes and leukemic proliferation.