Antigen receptor gene rearrangements reflect on the heterogeneity of adult Acute Lymphoblastic Leukaemia (ALL) with implications of cell-origin of ALL subgroups - a UKALLXII study.
Rai L., Casanova A., Moorman AV., Richards S., Buck G., Goldstone AH., Fielding AK., Foroni L.
Cytogenetic and molecular investigations of Acute Lymphoblastic Leukaemia (ALL) have identified the existence of distinct clinical subgroups. Molecular monitoring of clonal Immunoglobulin and T cell receptor (IG/TR) gene rearrangements has become an important tool in stratification of therapy of ALL. In order to determine whether certain features of the patient-specific rearrangements could hold further prognostic clues or provide information on the cell of origin of ALL, a comprehensive analysis of structural and biological features (V gene usage, coding frame and mutational status and complementarity-determining region -III length) of 473 IG/TR rearrangements identified in 229 adults with ALL was carried out. Distinct variable-gene usage profiles were identified between ALL subgroups, particularly for patients positive for BCR-ABL1 compared to MLL-AFF1 positive leukaemias; suggesting that the former is derived from a more mature B progenitor. Interestingly, occurrence of TRGV1-TRGV8 was prognostic for better event-free survival (31% at 4 years with vs. 0% at 4 years without, P = 0.05). The heterogeneity in clinical outcome is suggested by the basic molecular processes of antigen receptor gene rearrangements as shown in this work.